docs(changelog): fold post-3.3.0-draft commits into the 3.3.0 notes (#7921)

The `# 3.3.0` changelog section was written before ~8 commits landed on
develop. #7909 (dark mode) and #7918/#7911 (offline Docker boot) were already
captured; this adds the remaining user-facing change and dependency bumps so
the 3.3.0 release notes are complete:

- Notable fixes: #7910 — Firefox authorship-colour flake (early keystrokes
  tagged author='' before the async userAuthor propagated, producing an
  unattributed insert the pad-corruption guard rejected).
- Dependencies: mysql2 →3.22.5 (#7915), undici →8.4.1 (#7914), pdfkit
  →0.19.0 (#7916), @radix-ui/react-switch →1.3.0 (#7913), and the extra
  dev-dependency group bump (#7912).

Localisation (translatewiki) is already covered by the existing entry.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -28,6 +28,7 @@ A defence-in-depth pass across the API, token, export, and deployment surfaces:
 - **OIDC — fix broken `OIDCAdapter` flows (#7837).** Repairs the adapter flows and widens the storage type to include `string` for the `userCode` index; adds regression tests.
 - **Accessibility — dialog titles/descriptions and a missing l10n key (#7835 / #7836).** Adds the `index.code` key referenced by `index.html` but never defined (which produced a "Couldn't find translation key" console error on the landing page), and gives every admin `@radix-ui/react-dialog` `Dialog.Content` a `Dialog.Title` and `Dialog.Description` (visually hidden where there's no visible heading), silencing Radix's a11y warnings. A new backend spec fails CI if any `data-l10n-id` in `src/templates/*.html` is missing from `en.json`.
 - **Offline/air-gapped Docker boot — stop pnpm self-provisioning a pinned version (issue #7911).** The official image installs pnpm directly (corepack was dropped for Node 25+). Because the image's pnpm intentionally lags the `packageManager` pin in `package.json` (pnpm 11.1.x enforces a minimum-release-age policy the frozen-lockfile build can't satisfy), pnpm treated every call — including the informational `pnpm --version` probe Etherpad runs at startup — as a request to download the pinned build. Behind a firewall that download failed (`Failed to get pnpm version: … Command exited with code 1`), breaking startup. The Dockerfile now sets `pnpm_config_pm_on_fail=ignore`, and the startup probe plus the updater's pnpm-on-PATH checks run with the same flag, so pnpm uses the installed version instead of reaching for the network (without changing which pnpm runs the build-time install). A backend spec fails CI if that guard is dropped while a version gap exists.
+- **Firefox authorship colours — tag early keystrokes with the right author (#7910).** The inner editor's `thisAuthor` starts empty and is only populated when collab_client's queued `setProperty('userAuthor', userId)` reaches the iframe (applied asynchronously via `pendingInit`). Under Firefox timing the first keystrokes could beat it, so freshly typed text — and early line-attribute changes (lists, headings, alignment) — were tagged `author=''`, which canonicalises to an unattributed insert that the server's pad-corruption guard rejects, dropping the whole change and losing authorship (the intermittent `clear_authorship_color` flake, where undo couldn't restore the author colour). A `getLocalAuthor()` helper now falls back to `clientVars.userId` (the same id, available synchronously) whenever `thisAuthor` is still empty, applied at the text-insert sites and to seed `documentAttributeManager.author`; the intentional clear-authorship path and the server-side guard are unchanged.
 - **Dark mode — fix the white address bar and the light-flash on load (#7909, issue #7606).** Dark-mode users still saw a white mobile address bar above the dark toolbar, and the whole page flashed light before going dark. Both came from rendering the light state server-side and switching to dark only after the JS bundle ran: iOS Safari reads `theme-color` at parse time and doesn't reliably repaint on a later JS mutation, and the page painted light before the bundle applied the dark skin classes. The server now emits a `prefers-color-scheme`-scoped `theme-color` pair so the address bar is correct at first paint, plus a small blocking `<head>` script that applies the dark skin classes before the stylesheet paints. Both are gated on `enableDarkMode` (default on) and the colibris skin; `pad.ts` still runs on init to wire up the `#options-darkmode` toggle (which now updates every `theme-color` meta) and theme the editor iframes. Applies to the pad and timeslider views.
 
 ### Internal / contributor-facing
@@ -40,7 +41,7 @@ A defence-in-depth pass across the API, token, export, and deployment surfaces:
 ### Dependencies
 
 - Two major bumps: `redis` 5.12.1 → 6.0.0 (#7869) and `ejs` 5.0.2 → 6.0.1 (#7860).
-- `ueberdb2` 6.1.2 → 6.1.8, `mssql` 12.5.3 → 12.5.5, `nodemailer` 8.0.7 → 8.0.10, `mysql2` 3.22.3 → 3.22.4, `oidc-provider` 9.8.3 → 9.8.4, `@elastic/elasticsearch` 9.4.1 → 9.4.2, `lru-cache` 11.5.0 → 11.5.1, `rate-limiter-flexible` 11.1.0 → 11.1.1, `semver` 7.8.1 → 7.8.2, `js-cookie` 3.0.7 → 3.0.8, `tsx` 4.22.3 → 4.22.4, `@tanstack/react-query` 5.100.11 → 5.101.0 (+ devtools), plus `i18next`, `react-router-dom`, and several dev-dependency group bumps.
+- `ueberdb2` 6.1.2 → 6.1.8, `mssql` 12.5.3 → 12.5.5, `nodemailer` 8.0.7 → 8.0.10, `mysql2` 3.22.3 → 3.22.5 (#7915), `undici` 8.3.0 → 8.4.1 (#7914), `pdfkit` 0.18.0 → 0.19.0 (#7916), `oidc-provider` 9.8.3 → 9.8.4, `@elastic/elasticsearch` 9.4.1 → 9.4.2, `lru-cache` 11.5.0 → 11.5.1, `rate-limiter-flexible` 11.1.0 → 11.1.1, `semver` 7.8.1 → 7.8.2, `js-cookie` 3.0.7 → 3.0.8, `tsx` 4.22.3 → 4.22.4, `@radix-ui/react-switch` 1.2.6 → 1.3.0 (#7913), `@tanstack/react-query` 5.100.11 → 5.101.0 (+ devtools), plus `i18next`, `react-router-dom`, and several dev-dependency group bumps (#7912).
 
 ### Localisation