Merge remote-tracking branch 'origin/master' into session-query-trace

# Conflicts:
#	packages/session-query/session-query/README.md
#	packages/support/invariants/src/index.ts

packages/support/invariants/README.md

@@ -1,8 +1,8 @@
 # dsh-invariants
 
-Dev-mode event-contract assertions. This pure-listener plugin checks relationships among session events, agent states, scoped dispatches, and model requests at runtime; it does not own or change product behavior.
+Runtime event-contract assertions intended for development diagnostics. This pure-listener plugin checks relationships among session events, agent states, scoped dispatches, and model requests; it does not own or change product behavior.
 
-**Off in production.** Enable it in tests and the demos, where a contract violation should fail loudly. It costs nothing when not registered, and doubles as executable documentation of the event taxonomy — the assertions *are* the contract.
+The plugin has no environment guard: it is active wherever it is registered. The default [`dsh-agent-core`](../../core/agent-core/README.md) bundle mounts it unconditionally; a custom composition can omit it when the runtime cost is undesirable. It doubles as executable documentation of the event taxonomy — the assertions *are* the contract.
 
 Session itself owns immutable, surface-valid log storage in every composition: it takes one lossless JSON snapshot of each candidate, validates the complete surface transition, deep-freezes the accepted record, and exposes the log through immutable array snapshots. The invariants plugin checks the remaining cross-record and cross-seam rules that Session does not own.
 
@@ -45,8 +45,17 @@ On any violation it throws `InvariantError` (`code: 'INVARIANT'`).
 
 ## Why runtime assertions remain useful
 
-Session enforces the per-record storage boundary at runtime, where a cast cannot bypass it. Pervasive `DeepReadonly<SessionEvent>` types would add noise across consumers without expressing relationships such as turn/step nesting, subject-correct scoped dispatch, or equality between a request and its log reconstruction. This plugin checks those relationships in development while `dsh-session` keeps history immutable in every composition. See [source-owned session immutability and dev-mode invariants](../../../docs/rfc/implemented/architecture/2026-06-11-dev-invariants-over-deep-readonly.md).
+Session enforces the per-record storage boundary at runtime, where a cast cannot bypass it. Pervasive `DeepReadonly<SessionEvent>` types would add noise across consumers without expressing relationships such as turn/step nesting, subject-correct scoped dispatch, or equality between a request and its log reconstruction. This plugin checks those relationships wherever it is mounted while `dsh-session` keeps history immutable in every composition. See [source-owned session immutability and dev-mode invariants](../../../docs/rfc/implemented/architecture/2026-06-11-dev-invariants-over-deep-readonly.md).
 
 ## Seeded sessions
 
 A seeded or forked session arrives with events already in its log because construction does not emit `session/event` for each seed record. `Session` validates, snapshots, and freezes every seed record before accepting it; on `session/created`, this plugin replays the accepted log only to rebuild and check its relational trace state.
+
+## Model Experience
+
+None, as this observer only validates events and frozen requests and never rewrites prompts, schemas, messages, or streams.
+
+## Known Limitations and Deferred Work
+
+- **The request-reconstructability assertion covers loop-built requests only** — hand-built one-shots (e.g. compaction's summarize call) carry no live `sessionId` marker and are skipped.
+- **Merge-extended event families get no family-specific assertions** — `compact/*` lock pairing and `hook/*` invoked/result pairing are not checked here; only the core turn/step/chunk/tool-result contract is.