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/bash-local/tests/executor.spec.ts

@@ -110,7 +110,7 @@ describe('LocalBashExecutor.run', () => {
   it('resolve() carries stdin/env onto the spec, and run() threads them to the command', async () => {
     const { bash } = await setup()
     const spec = bash.resolve({ command: 'cat; echo "[$DSH_SEAM_VAR]"', stdin: 'piped\n', env: { DSH_SEAM_VAR: 'env-ok' } })
-    // resolve() keeps the trusted-plugin fields verbatim (optional, no default).
+    // resolve() keeps the stdin/env fields verbatim (optional, no default).
     expect(spec.stdin).toBe('piped\n')
     expect(spec.env).toEqual({ DSH_SEAM_VAR: 'env-ok' })
     const result = await bash.run(spec)

packages/bash/bash-local/tests/run.spec.ts

@@ -158,7 +158,7 @@ describe('runBash', () => {
   })
 })
 
-describe('stdin and extra env (trusted-plugin surface)', () => {
+describe('stdin and extra env (set by in-process plugins)', () => {
   it('writes stdin to the command and closes it', async () => {
     const result = await runBash(spec('cat', { stdin: 'hello from stdin\n' })).done
     expect(result.exitCode).toBe(0)