feat(web,ui): per-project forced git provider and settings gating

Adds a per-project forced provider (github|gitlab|gitea) on top of the
per-project API base URL overrides: stored under gitProviders.provider in
projects/<projectId>.json, sanitized server-side, and winning over remote-host
detection both in useGitProvider and in server repo resolution
(parseGitLabRemoteUrl/parseGiteaRemoteUrl accept any host when the provider
is forced). The Projects settings page replaces the three always-visible URL
fields with a provider selector (auto-detect + the three forges) and one URL
override for the active provider. Global provider override fields on the
GitHub/GitLab/Gitea settings tabs now render only once an account is
connected, and Settings search availability matches that gating.

Also fixes the useConfigStore/useDirectoryStore circular-import TDZ in the
bundled chunk via the window-registered store handle and defers the directory
subscription to a microtask; fixes the Gitea PR merge payload (Do carries the
merge-style string enum, not a boolean + MergeMethod); and adds a documented
Gitea client live-test harness (scripts/gitea-live-test.ts + client.d.ts).

package.json

@@ -80,6 +80,7 @@
     "icons:sprite": "node scripts/generate-file-type-sprite.mjs",
     "icons:generate": "bun run scripts/generate-icon-sprite.mjs",
     "themes:port:opencode": "tsx scripts/port-opencode-theme.ts",
+    "gitea:live-test": "bun packages/web/scripts/gitea-live-test.ts",
     "version:bump": "node scripts/bump-version.mjs",
     "release:prepare": "bun run build && bun run type-check && bun run lint",
     "release:test": "./scripts/test-release-build.sh",