fix(i18n): check every locale module, not the three named ones

[Longado]

Summary

check-i18n discovered locale-module manifests through a hardcoded three-name allowlist (tuttiI18nModule, agentGuiI18nModule, browserNodeI18nModule), while docs/conventions/static-analysis.md documents those same three as non-exhaustive examples of a package-specific name ("such as"). Four shipped manifests chose names outside the list and were silently excluded from every i18n check (locale-key parity, placeholder parity, hardcoded-copy scan):

• richTextI18nModule (packages/ui/rich-text)
• issueManagerI18nModule (packages/workspace/issue-manager)
• terminalNodeI18nModule (packages/workspace/terminal)
• workspaceUserProjectI18nModule (packages/workspace/user-project)

Discovery now matches any export const <name>I18nModule; non-manifest matches are still discarded by parseExportedObjectLiteral returning null.

The remaining changes are what that coverage requires, not separate concerns:

• All four previously-skipped manifests name their namespace through a sibling constant (namespace: richTextI18nNamespace) rather than a literal, which threw ReferenceError once they were discovered. The manifest VM context now carries the module's top-level double-quoted string constants.
• Interpolated strings were read as static text, so label: `@${label}` was reported as hardcoded copy and t(`status.${status}`) as a missing key. Copy that is only placeholders plus punctuation is no longer reported, and a key composed at runtime is skipped; prose that survives placeholder removal (Hello ${name}, welcome) still reports.
• controllerActionTestHarness.ts (imported only by *.test.ts files) gets the same exemption .test.ts carries, via a TestHarness.ts(x) suffix entry.

Coverage grows from 4,317 keys / 2,082 source files to 4,604 / 2,275. No user-visible behavior changes; this is a check-script fix.

Verification

• node --test tools/scripts/check-i18n.test.mjs — 15/15 pass (13 existing + 2 new)
• node tools/scripts/check-i18n.mjs — passes on the real tree at the new coverage
• oxfmt --check clean on both files
• Behavioral proof: deleting status.running from the terminal module's zh-CN locale passes silently on main and is caught by this branch as locale-key-missing terminalNode.status.running. The new regression test asserts exactly that and fails against the unmodified script.

Checklist

• This PR does not change agent lifecycle semantics (tooling-script only).
• I kept the change focused on one concern.
• Documentation: docs/conventions/static-analysis.md already describes the intended (example-based) behavior; the script now matches it, so no doc change is needed.
• No README/CONTRIBUTING language-variant changes involved.
• I ran the lowest meaningful local checks for the changed surface (unit suite + real-tree run + formatter).
• Commit is signed off with DCO (git commit -s).