feat: migrate from Cedar to SpiceDB authorization system

This is a major architectural change that replaces the Cedar policy-based
authorization system with SpiceDB's relation-based authorization.

Key changes:

- Migrate from Rust to Go implementation
- Replace Cedar policies with SpiceDB schema and relationships
- Switch from envoy `ext_authz` with Cedar to SpiceDB permission checks
- Update build system and dependencies for Go ecosystem
- Maintain Envoy integration for external authorization

This change enables more flexible permission modeling through SpiceDB's
Google Zanzibar inspired relation-based system, supporting complex
hierarchical permissions that were difficult to express in Cedar.

Breaking change: Existing Cedar policies and Rust-based configuration
will no longer work and need to be migrated to SpiceDB schema.

1 files changed, 0 insertions, 335 deletions

diff --git a/vendor/base64/src/read/decoder.rs b/vendor/base64/src/read/decoder.rs
deleted file mode 100644
index 781f6f88..00000000
--- a/vendor/base64/src/read/decoder.rs
+++ /dev/null
@@ -1,335 +0,0 @@
-use crate::{engine::Engine, DecodeError, DecodeSliceError, PAD_BYTE};
-use std::{cmp, fmt, io};
-
-// This should be large, but it has to fit on the stack.
-pub(crate) const BUF_SIZE: usize = 1024;
-
-// 4 bytes of base64 data encode 3 bytes of raw data (modulo padding).
-const BASE64_CHUNK_SIZE: usize = 4;
-const DECODED_CHUNK_SIZE: usize = 3;
-
-/// A `Read` implementation that decodes base64 data read from an underlying reader.
-///
-/// # Examples
-///
-/// ```
-/// use std::io::Read;
-/// use std::io::Cursor;
-/// use base64::engine::general_purpose;
-///
-/// // use a cursor as the simplest possible `Read` -- in real code this is probably a file, etc.
-/// let mut wrapped_reader = Cursor::new(b"YXNkZg==");
-/// let mut decoder = base64::read::DecoderReader::new(
-///     &mut wrapped_reader,
-///     &general_purpose::STANDARD);
-///
-/// // handle errors as you normally would
-/// let mut result = Vec::new();
-/// decoder.read_to_end(&mut result).unwrap();
-///
-/// assert_eq!(b"asdf", &result[..]);
-///
-/// ```
-pub struct DecoderReader<'e, E: Engine, R: io::Read> {
-    engine: &'e E,
-    /// Where b64 data is read from
-    inner: R,
-
-    /// Holds b64 data read from the delegate reader.
-    b64_buffer: [u8; BUF_SIZE],
-    /// The start of the pending buffered data in `b64_buffer`.
-    b64_offset: usize,
-    /// The amount of buffered b64 data after `b64_offset` in `b64_len`.
-    b64_len: usize,
-    /// Since the caller may provide us with a buffer of size 1 or 2 that's too small to copy a
-    /// decoded chunk in to, we have to be able to hang on to a few decoded bytes.
-    /// Technically we only need to hold 2 bytes, but then we'd need a separate temporary buffer to
-    /// decode 3 bytes into and then juggle copying one byte into the provided read buf and the rest
-    /// into here, which seems like a lot of complexity for 1 extra byte of storage.
-    decoded_chunk_buffer: [u8; DECODED_CHUNK_SIZE],
-    /// Index of start of decoded data in `decoded_chunk_buffer`
-    decoded_offset: usize,
-    /// Length of decoded data after `decoded_offset` in `decoded_chunk_buffer`
-    decoded_len: usize,
-    /// Input length consumed so far.
-    /// Used to provide accurate offsets in errors
-    input_consumed_len: usize,
-    /// offset of previously seen padding, if any
-    padding_offset: Option<usize>,
-}
-
-// exclude b64_buffer as it's uselessly large
-impl<'e, E: Engine, R: io::Read> fmt::Debug for DecoderReader<'e, E, R> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("DecoderReader")
-            .field("b64_offset", &self.b64_offset)
-            .field("b64_len", &self.b64_len)
-            .field("decoded_chunk_buffer", &self.decoded_chunk_buffer)
-            .field("decoded_offset", &self.decoded_offset)
-            .field("decoded_len", &self.decoded_len)
-            .field("input_consumed_len", &self.input_consumed_len)
-            .field("padding_offset", &self.padding_offset)
-            .finish()
-    }
-}
-
-impl<'e, E: Engine, R: io::Read> DecoderReader<'e, E, R> {
-    /// Create a new decoder that will read from the provided reader `r`.
-    pub fn new(reader: R, engine: &'e E) -> Self {
-        DecoderReader {
-            engine,
-            inner: reader,
-            b64_buffer: [0; BUF_SIZE],
-            b64_offset: 0,
-            b64_len: 0,
-            decoded_chunk_buffer: [0; DECODED_CHUNK_SIZE],
-            decoded_offset: 0,
-            decoded_len: 0,
-            input_consumed_len: 0,
-            padding_offset: None,
-        }
-    }
-
-    /// Write as much as possible of the decoded buffer into the target buffer.
-    /// Must only be called when there is something to write and space to write into.
-    /// Returns a Result with the number of (decoded) bytes copied.
-    fn flush_decoded_buf(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        debug_assert!(self.decoded_len > 0);
-        debug_assert!(!buf.is_empty());
-
-        let copy_len = cmp::min(self.decoded_len, buf.len());
-        debug_assert!(copy_len > 0);
-        debug_assert!(copy_len <= self.decoded_len);
-
-        buf[..copy_len].copy_from_slice(
-            &self.decoded_chunk_buffer[self.decoded_offset..self.decoded_offset + copy_len],
-        );
-
-        self.decoded_offset += copy_len;
-        self.decoded_len -= copy_len;
-
-        debug_assert!(self.decoded_len < DECODED_CHUNK_SIZE);
-
-        Ok(copy_len)
-    }
-
-    /// Read into the remaining space in the buffer after the current contents.
-    /// Must only be called when there is space to read into in the buffer.
-    /// Returns the number of bytes read.
-    fn read_from_delegate(&mut self) -> io::Result<usize> {
-        debug_assert!(self.b64_offset + self.b64_len < BUF_SIZE);
-
-        let read = self
-            .inner
-            .read(&mut self.b64_buffer[self.b64_offset + self.b64_len..])?;
-        self.b64_len += read;
-
-        debug_assert!(self.b64_offset + self.b64_len <= BUF_SIZE);
-
-        Ok(read)
-    }
-
-    /// Decode the requested number of bytes from the b64 buffer into the provided buffer. It's the
-    /// caller's responsibility to choose the number of b64 bytes to decode correctly.
-    ///
-    /// Returns a Result with the number of decoded bytes written to `buf`.
-    ///
-    /// # Panics
-    ///
-    /// panics if `buf` is too small
-    fn decode_to_buf(&mut self, b64_len_to_decode: usize, buf: &mut [u8]) -> io::Result<usize> {
-        debug_assert!(self.b64_len >= b64_len_to_decode);
-        debug_assert!(self.b64_offset + self.b64_len <= BUF_SIZE);
-        debug_assert!(!buf.is_empty());
-
-        let b64_to_decode = &self.b64_buffer[self.b64_offset..self.b64_offset + b64_len_to_decode];
-        let decode_metadata = self
-            .engine
-            .internal_decode(
-                b64_to_decode,
-                buf,
-                self.engine.internal_decoded_len_estimate(b64_len_to_decode),
-            )
-            .map_err(|dse| match dse {
-                DecodeSliceError::DecodeError(de) => {
-                    match de {
-                        DecodeError::InvalidByte(offset, byte) => {
-                            match (byte, self.padding_offset) {
-                                // if there was padding in a previous block of decoding that happened to
-                                // be correct, and we now find more padding that happens to be incorrect,
-                                // to be consistent with non-reader decodes, record the error at the first
-                                // padding
-                                (PAD_BYTE, Some(first_pad_offset)) => {
-                                    DecodeError::InvalidByte(first_pad_offset, PAD_BYTE)
-                                }
-                                _ => {
-                                    DecodeError::InvalidByte(self.input_consumed_len + offset, byte)
-                                }
-                            }
-                        }
-                        DecodeError::InvalidLength(len) => {
-                            DecodeError::InvalidLength(self.input_consumed_len + len)
-                        }
-                        DecodeError::InvalidLastSymbol(offset, byte) => {
-                            DecodeError::InvalidLastSymbol(self.input_consumed_len + offset, byte)
-                        }
-                        DecodeError::InvalidPadding => DecodeError::InvalidPadding,
-                    }
-                }
-                DecodeSliceError::OutputSliceTooSmall => {
-                    unreachable!("buf is sized correctly in calling code")
-                }
-            })
-            .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?;
-
-        if let Some(offset) = self.padding_offset {
-            // we've already seen padding
-            if decode_metadata.decoded_len > 0 {
-                // we read more after already finding padding; report error at first padding byte
-                return Err(io::Error::new(
-                    io::ErrorKind::InvalidData,
-                    DecodeError::InvalidByte(offset, PAD_BYTE),
-                ));
-            }
-        }
-
-        self.padding_offset = self.padding_offset.or(decode_metadata
-            .padding_offset
-            .map(|offset| self.input_consumed_len + offset));
-        self.input_consumed_len += b64_len_to_decode;
-        self.b64_offset += b64_len_to_decode;
-        self.b64_len -= b64_len_to_decode;
-
-        debug_assert!(self.b64_offset + self.b64_len <= BUF_SIZE);
-
-        Ok(decode_metadata.decoded_len)
-    }
-
-    /// Unwraps this `DecoderReader`, returning the base reader which it reads base64 encoded
-    /// input from.
-    ///
-    /// Because `DecoderReader` performs internal buffering, the state of the inner reader is
-    /// unspecified. This function is mainly provided because the inner reader type may provide
-    /// additional functionality beyond the `Read` implementation which may still be useful.
-    pub fn into_inner(self) -> R {
-        self.inner
-    }
-}
-
-impl<'e, E: Engine, R: io::Read> io::Read for DecoderReader<'e, E, R> {
-    /// Decode input from the wrapped reader.
-    ///
-    /// Under non-error circumstances, this returns `Ok` with the value being the number of bytes
-    /// written in `buf`.
-    ///
-    /// Where possible, this function buffers base64 to minimize the number of read() calls to the
-    /// delegate reader.
-    ///
-    /// # Errors
-    ///
-    /// Any errors emitted by the delegate reader are returned. Decoding errors due to invalid
-    /// base64 are also possible, and will have `io::ErrorKind::InvalidData`.
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        if buf.is_empty() {
-            return Ok(0);
-        }
-
-        // offset == BUF_SIZE when we copied it all last time
-        debug_assert!(self.b64_offset <= BUF_SIZE);
-        debug_assert!(self.b64_offset + self.b64_len <= BUF_SIZE);
-        debug_assert!(if self.b64_offset == BUF_SIZE {
-            self.b64_len == 0
-        } else {
-            self.b64_len <= BUF_SIZE
-        });
-
-        debug_assert!(if self.decoded_len == 0 {
-            // can be = when we were able to copy the complete chunk
-            self.decoded_offset <= DECODED_CHUNK_SIZE
-        } else {
-            self.decoded_offset < DECODED_CHUNK_SIZE
-        });
-
-        // We shouldn't ever decode into decoded_buffer when we can't immediately write at least one
-        // byte into the provided buf, so the effective length should only be 3 momentarily between
-        // when we decode and when we copy into the target buffer.
-        debug_assert!(self.decoded_len < DECODED_CHUNK_SIZE);
-        debug_assert!(self.decoded_len + self.decoded_offset <= DECODED_CHUNK_SIZE);
-
-        if self.decoded_len > 0 {
-            // we have a few leftover decoded bytes; flush that rather than pull in more b64
-            self.flush_decoded_buf(buf)
-        } else {
-            let mut at_eof = false;
-            while self.b64_len < BASE64_CHUNK_SIZE {
-                // Copy any bytes we have to the start of the buffer.
-                self.b64_buffer
-                    .copy_within(self.b64_offset..self.b64_offset + self.b64_len, 0);
-                self.b64_offset = 0;
-
-                // then fill in more data
-                let read = self.read_from_delegate()?;
-                if read == 0 {
-                    // we never read into an empty buf, so 0 => we've hit EOF
-                    at_eof = true;
-                    break;
-                }
-            }
-
-            if self.b64_len == 0 {
-                debug_assert!(at_eof);
-                // we must be at EOF, and we have no data left to decode
-                return Ok(0);
-            };
-
-            debug_assert!(if at_eof {
-                // if we are at eof, we may not have a complete chunk
-                self.b64_len > 0
-            } else {
-                // otherwise, we must have at least one chunk
-                self.b64_len >= BASE64_CHUNK_SIZE
-            });
-
-            debug_assert_eq!(0, self.decoded_len);
-
-            if buf.len() < DECODED_CHUNK_SIZE {
-                // caller requested an annoyingly short read
-                // have to write to a tmp buf first to avoid double mutable borrow
-                let mut decoded_chunk = [0_u8; DECODED_CHUNK_SIZE];
-                // if we are at eof, could have less than BASE64_CHUNK_SIZE, in which case we have
-                // to assume that these last few tokens are, in fact, valid (i.e. must be 2-4 b64
-                // tokens, not 1, since 1 token can't decode to 1 byte).
-                let to_decode = cmp::min(self.b64_len, BASE64_CHUNK_SIZE);
-
-                let decoded = self.decode_to_buf(to_decode, &mut decoded_chunk[..])?;
-                self.decoded_chunk_buffer[..decoded].copy_from_slice(&decoded_chunk[..decoded]);
-
-                self.decoded_offset = 0;
-                self.decoded_len = decoded;
-
-                // can be less than 3 on last block due to padding
-                debug_assert!(decoded <= 3);
-
-                self.flush_decoded_buf(buf)
-            } else {
-                let b64_bytes_that_can_decode_into_buf = (buf.len() / DECODED_CHUNK_SIZE)
-                    .checked_mul(BASE64_CHUNK_SIZE)
-                    .expect("too many chunks");
-                debug_assert!(b64_bytes_that_can_decode_into_buf >= BASE64_CHUNK_SIZE);
-
-                let b64_bytes_available_to_decode = if at_eof {
-                    self.b64_len
-                } else {
-                    // only use complete chunks
-                    self.b64_len - self.b64_len % 4
-                };
-
-                let actual_decode_len = cmp::min(
-                    b64_bytes_that_can_decode_into_buf,
-                    b64_bytes_available_to_decode,
-                );
-                self.decode_to_buf(actual_decode_len, buf)
-            }
-        }
-    }
-}