fix(ci): widen the locale hygiene gate to its blind spots

[orangeCatDeveloper]

Summary

The locale hygiene gate had three blind spots, and each one already has a live instance behind it.

SCOPE covered apps/desktop/src, packages/core/src and packages/ui/src — not packages/runtime-host/src. That is the one package where const zh = locale !== 'en' survives (client/host-handoff-copy.ts:33), the exact shape locale-literal-compare exists to reject, in the only tree the rules never opened.

Two patterns had no rule at all:

• A Han fallback handed to generalizedErrorMessage. That helper always renders en (redaction.ts:293), so a Chinese fallback makes the surface switch language by error content: classifiable errors read English, unclassifiable ones read Chinese, on the same screen.
• A literal title in a native open/save dialog. No catalog covers those panels, so a literal there ships one language to every locale. That is how eight of them accumulated.

The gate is a ratchet against the merge base, so this does not ask anyone to fix history: existing hits are grandfathered per (file, rule) and only growth fails.

Refs #2672

Verification

check-locale-hygiene                 passed, no new hits
check-locale-hygiene.test.mjs        7 pass / 0 fail (2 new)
npm run format:check                 clean

Baseline hits the ratchet now grandfathers, counted over SCOPE at this commit:

han-fallback-to-en-helper   1   apps/desktop/src/main/bot-incoming-main.ts:395
native-dialog-literal       4   pet-pack-import.ts, runtime-host-boot.ts (×2),
                                runtime-host-skills-ipc-main.ts

The four dialog literals are removed by #5179; this PR does not depend on it, and lands the rule whichever merges first. The bot-incoming-main.ts hit is real and stays: that whole bot-reply surface is hardcoded Chinese, so fixing it means giving it a catalog and a locale, which is its own change.

Each new rule is tested against a positive case and the shapes it must not flag — an English fallback to the same helper (how logs and CLI output legitimately use it), a catalog lookup in the title position, and a title property outside a dialog call.

Review focus

native-dialog-literal recognizes a dialog call by a properties: [ within 400 characters of the literal, rather than by resolving the callee. Dialog options are the only place that key appears in this shape, and the alternative — an AST pass — would cost the check its install-free property, which is why it runs before npm ci in CI. It will miss a showSaveDialog that passes no properties; filters-only save panels are not covered.

AI use

Select exactly one:

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: Claude Code — measured the blind spots against the tree, wrote the rules and their tests, and wrote this description. The commit carries a Generated-by: Claude Code trailer.

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — described under Summary above
• No