docs(bash): purge remaining trusted-plugin wording caught in review

Codex review of the reframe found stale "trusted-plugin surface/boundary"
wording still in review-relevant spots the first pass missed:

- docs/rfc/README.md index title for the RFC.
- packages/bash/bash-local/src/run.ts (childEnv JSDoc + SpawnSpec stdin/env
  JSDoc + the spawn stdin comment) and src/index.ts (resolve carry-through
  comment); run.ts also pointed at a tool-bash README section name that no
  longer exists.
- the two bash-local test descriptors (run.spec.ts / executor.spec.ts).
- the tool-bash guard test's `boundary-*` call ids and one "boundary
  assertion" comment (renamed to `no-forward-*`).

All reworded to the scrub-is-the-control framing (or neutral wording). The RFC
FILENAME keeps `-trusted-plugin-surface` as a stable id (many links point at it;
the index title and content are corrected). No code or behavior change.

packages/bash/tool-bash/tests/tools.spec.ts

@@ -924,7 +924,7 @@ describe('the model-facing bash tool builds its request from named args only (no
     // var or feed stdin via shell syntax anyway; this just keeps the request
     // shape honest so a future `...args` spread can't silently forward input.)
     await ctx.tools.execute({
-      callId: CallId('boundary-1'),
+      callId: CallId('no-forward-1'),
       name: 'bash',
       arguments: {
         command: 'echo hi',
@@ -943,9 +943,9 @@ describe('the model-facing bash tool builds its request from named args only (no
   it('a background bash call likewise carries no env/stdin', async () => {
     const { ctx, bash } = await setupRecording()
     // start() throws in this recorder, but resolve() runs first and records the
-    // request — which is all this boundary assertion needs.
+    // request — which is all this no-forward assertion needs.
     await ctx.tools.execute({
-      callId: CallId('boundary-2'),
+      callId: CallId('no-forward-2'),
       name: 'bash',
       arguments: {
         command: 'sleep 1',