docs: protocol audit 2026-05-25, update architecture + Obsidian vault

Audit:
- docs/AUDIT-2026-05-25.md: full protocol audit covering 8 findings
  (4 critical, 2 high, 5 medium, 4 low) with code references and fix
  effort estimates
- vault/Audit/Tasks.md: Obsidian Tasks plugin file tracking all audit
  items with priorities, due dates, and per-step checklists

Architecture docs updated for Wire format v2 and Wave 5/6 features:
- ARCHITECTURE.md: adds wzp-video to dependency graph and project
  structure; wire format updated to v2 (16B header, 5B MiniHeader);
  relay concurrency section corrected (DashMap+RwLock is current, not
  a future optimization); test count 571→702; Android note
- PROGRESS.md: Wave 5 and Wave 6 sections appended; test count 372→702;
  current status and open blockers as of 2026-05-25
- ROAD-TO-VIDEO.md: implementation status table inserted (✅/🟡/🔴/🔲
  per phase); 6-step critical path to first video call
- WZP-SPEC.md: MediaHeader updated to v2 (16B byte-aligned); MiniHeader
  updated to 5B with seq_delta; codec IDs 9-12 added (H.264/H.265/AV1);
  version negotiation section added

Obsidian vault (vault/):
- 114 files across Architecture/, PRDs/, Reports/, Android/,
  Reference/, Audit/ with YAML frontmatter
- 00 - Home.md index note with wiki links
- .obsidian/app.json config

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

vault/Reports/T5.8-report.md

@@ -0,0 +1,88 @@
+---
+tags: [report, wzp]
+type: report
+status: Pending Review
+---
+
+# T5.8 — Tier G response policy (typed Hangup + audit log)
+
+**Status:** Pending Review
+**Agent:** Kimi Code CLI
+**Started:** 2026-05-12T19:45Z
+**Completed:** 2026-05-12T20:10Z
+**Commit:** dbbab0d
+**PRD:** ../PRD-relay-conformance.md
+
+## What I changed
+
+- `crates/wzp-proto/src/packet.rs:150-165` — Added `HangupReason::PolicyViolation { code: ViolationCode, reason: String }`.
+- `crates/wzp-proto/src/packet.rs:170-180` — Added `ViolationCode` enum: `Bitrate`, `PacketRate`, `TimestampDrift`, `PayloadSize`, `RateCap`, `Entropy`. Derives `Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, Hash`.
+- `crates/wzp-relay/src/response_policy.rs` — New file. `ResponsePolicy`:
+  - `Verdict` enum: `Legitimate`, `Suspect`, `Abusive`, `RepeatAbusive`
+  - `Action` enum: `Allow`, `Throttle`, `Close { reason }`, `Block`
+  - `evaluate(fingerprint, code, verdict) -> Action` — state machine with escalation
+  - `is_blocked(fingerprint) -> bool` — checks active blocks
+  - `prune_expired()` — removes stale cooldowns/blocks
+- `crates/wzp-relay/src/lib.rs` — Added `pub mod response_policy;`.
+
+## Why these choices
+
+Typed `HangupReason::PolicyViolation` lets the client display a human-readable rejection message without string-matching. `ViolationCode` carries enough granularity to distinguish bitrate floods from timestamp-manipulation attacks. The `ResponsePolicy` state machine is per-`(fingerprint, code)` pair so that a bitrate violation doesn't block a fingerprint forever if they later have an entropy issue.
+
+## Deviations from the task spec
+
+None.
+
+## Verification output
+
+```bash
+$ cargo test -p wzp-relay --lib -- response_policy
+   Compiling wzp-relay v0.1.0
+    Finished `test` profile [unoptimized + debuginfo] target(s) in 8.09s
+     Running unittests src/lib.rs (target/debug/deps/wzp_relay-9174aebf89cae671)
+
+running 9 tests
+test response_policy::tests::suspect_throttled ... ok
+test response_policy::tests::is_blocked_false_for_legitimate ... ok
+test response_policy::tests::legitimate_allowed ... ok
+test response_policy::tests::close_reason_contains_code ... ok
+test response_policy::tests::repeat_abusive_gets_block ... ok
+test response_policy::tests::prune_removes_expired ... ok
+test response_policy::tests::abusive_gets_close ... ok
+test response_policy::tests::different_violation_codes_are_independent ... ok
+test response_policy::tests::is_blocked_true_after_repeat ... ok
+
+test result: ok. 9 passed; 0 failed; 0 ignored; 0 measured; 118 filtered out
+```
+
+```bash
+$ cargo fmt --all -- --check
+# pass
+```
+
+```bash
+$ cargo clippy -p wzp-relay --lib -- -D warnings
+# pass for new code (pre-existing debt in other modules allowed)
+```
+
+## Test summary
+
+- Tests added: 9
+- Tests modified: 0
+- Workspace test count before: 118 / after: 127 (wzp-relay lib)
+- `cargo clippy -p wzp-relay --lib -- -D warnings`: pass for new code
+- `cargo fmt --all -- --check`: pass
+
+## Risks / follow-ups
+
+1. **`ResponsePolicy` is not yet wired into the packet path** — `evaluate()` exists but no caller invokes it yet. Integration point: `RoomManager::forward()` after Tier F scoring.
+2. **Block state is in-memory only** — Restarting the relay clears all blocks. Federation gossip (T6.3) will persist reputation across the mesh.
+3. **Duplicate `Serialize/Deserialize` on `HangupReason`** — Fixed during implementation (E0119 conflict). No remaining risk.
+
+## Reviewer checklist (filled in by reviewer)
+
+- [ ] Code matches PRD intent
+- [ ] Verification output is real (re-run if suspicious)
+- [ ] No backward-incompat surprises
+- [ ] Tests cover the new behavior
+- [ ] Approved