fix(desktop): carry typed OAuth failure reasons from main-process producers

[orangeCatDeveloper]

Summary

Stacked on #4551; review the last commit only.

subscriptionResultMessage matches two English Host messages with regexes to localize OAuth login failures. One of the three regex families — did not present OAuth|no matching OAuth presentation — describes failures produced by Desktop itself, not the Host: the presentation timeout and the absent-request throw in runtime-host-oauth-presentation.ts. This PR gives those producers a typed error (OAuthPresentationError with presentation_timeout / presentation_absent) and maps it, along with the Host's operation_conflict, to typed reasons on the get-auth-url failure envelope:

• operation_conflict → login_in_progress
• OAuthPresentationError → presentation_failed
• operation_unavailable → experimental_disabled (unchanged)

The renderer catalog maps the two new reasons per locale and the prose regex is deleted. The enrollment is disabled and already in progress fallbacks stay: their producers live in the Runtime Host, which may be remote and older than this client — that is a version-skew fallback, not dead code. loginConflict / browserPresentFailed ad-hoc keys are folded into resultCodes (same wording).

Refs #2672

Verification

apps/desktop typecheck (4 tsconfigs): 0 errors
oauth-result-copy.test.ts: 6 pass (2 new: typed reasons per locale; regex-removal pin)
focused desktop suites: pass
renderer architecture check: passed
biome (changed files): clean
protocol epoch guard: no protocol changes

Not run: Electron e2e with a live Host login flow.

AI use

• Generative tooling made a substantive contribution

Tool(s) and scope: Claude Code traced the producer→presenter path, implemented the typed error and reason mapping, removed the regex, added the tests, and wrote this description. Commit carries Generated-by: Claude Code.

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 — login-conflict and browser-presentation failures now render the same catalog copy via typed reasons instead of English prose matching.