fix(#829): enforce repository-wide runtime launch choke point

docs/architecture/mutator-class-gate.md

@@ -35,6 +35,28 @@ A receipt is only a future promotion prerequisite. It is not an obedience, resid
 
 The executable submits the runtime's actual tool name to `authorize_tool`. Missing identity, malformed input/reply, timeout, broker unavailability, or denial exits with status 2 and blocks fail-closed.
 
+## Runtime-launch choke-point and permanent guard
+
+Every repository-owned Claude/Pi launch entry converges on `launch-runtime.py`, either directly or through `mosaic` → `execLeaseGatedRuntime`. PRDY init/update and QA remediation invoke the wrapper directly so their existing prompts, dangerous-permission flags, working directory, and environment survive without skipping broker registration. `@mosaicstack/coord` rewrites direct Claude commands to `mosaic claude` and rejects unknown custom Claude launchers.
+
+`check-runtime-launches.py` is the permanent completeness guard. It scans production shell, TypeScript/JavaScript, Python, and data launch definitions under `packages/`, `apps/`, `plugins/`, and `tools/`; direct literal, absolute-path, process-API, and dynamic runtime launches fail. It is mandatory in `@mosaicstack/mosaic`'s test script, so root CI fails when a future entry does not name the wrapper, `execLeaseGatedRuntime`, or a gated `mosaic` launch. Synthetic scanner tests prove representative bypass forms are rejected, while real-socket tests prove PRDY init/update and QA receive broker sessions and deny an unverified mutator.
+
+The live inventory is emitted by:
+
+```bash
+python3 packages/mosaic/framework/tools/lease-broker/check-runtime-launches.py --root . --json
+```
+
+| Production launch family                               | Gated entries |
+| ------------------------------------------------------ | ------------: |
+| `@mosaicstack/coord` default/configured Claude command |             2 |
+| Fleet runtime start                                    |             1 |
+| QA remediation + generated QA command                  |             2 |
+| Orchestrator command construction/session launches     |             3 |
+| PRDY init/update                                       |             2 |
+| Mosaic Claude/Pi/Claudex adapter and wrapper boundary  |             4 |
+| **Total**                                              |   **14 / 14** |
+
 ## Assurance boundary
 
 This closes T-A after an observer fires or lease expiry and T-B for in-runtime tool calls. Hook/extension absence, a runtime executing outside the gated launcher, ptrace/same-UID broker replacement, and other fully rotted behavior remain T-C. Server-side branch protection and required PR review/CI remain the irreducible line for protected repository mutations.