fix(i18n): emit settings expected-result codes from producers

[orangeCatDeveloper]

Summary

Settings-area producers emitted zh-only result strings, so English users either saw Chinese or — where consumers guarded with /[㐀-鿿]/ content sniffing — silently lost the information (permission guidance was dropped entirely). Producers now emit stable machine codes (IPC payloads stay locale-free), and each settings catalog maps its union exhaustively per locale with an explicit unknown-code fallback. Every CJK-sniff site in this area dies with its producer fixed; zh copy moved verbatim, en copy is new.

Covered producers: capability-snapshot reasons, memory ops, test-connection OAuth rate-limit, computer-use-host health reasons, the GitHub Copilot import path (github-copilot-local-credential + its IPC handler, re-based onto main's device-grant rewrite), plus the dev-singleton dialog, browser message-box close label, and artifact/config native dialog titles (wired through the main-process locale authority). subscriptionResultMessage now takes the result envelope and resolves code, then the typed reason (experimental_disabled), through the catalog before falling back to the keyword classifier; its trailing CJK passthrough is gone. It moved out of the useOAuthLoginFlow hook module into the catalog module beside the copy it renders, which also makes it testable from node.

The bot domain moved to its own PR so each PR is one reviewer context.

Refs #2672

Verification

apps/desktop typecheck (4 tsconfigs):   0 errors
workspace typecheck:                    0 errors
desktop main tests (dist):              2000 pass / 0 fail
rendered-output tests (en+zh):          Copilot code, experimental_disabled reason, unknown code → fallback
packages/core tests:                    774 pass / 0 fail
CJK-sniff regexes in touched files:     0 remaining
zh literals in copilot producers:       0 remaining (was 8)
renderer architecture check:            passed against origin/main
biome (changed files):                  clean

Boundaries: the four legacy capability reason tokens keep their existing prose form — #4524's health presenter maps that exact vocabulary, so renaming is a coordinated follow-up.

AI use

Select exactly one:

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

Tool(s) and scope: Claude Code — analysis, implementation, tests, and this description, under the contributor's direction; the commit carries a Generated-by: Claude Code trailer.

Checklist

• Tests cover the change and fail without it