v1.91.4.0 fix: Windows Opera cookie import wave (#2980, refs #2957) (#2987)

* fix: support Windows Opera and Opera GX cookie imports

Fixes #2957

* fix: repair Windows cookie decryption and make Opera import failures actionable

- strip the SHA-256(host_key) prefix Chromium adds to v10 values (DB meta v24+) on Windows
- keep receipts and name `$B handoff` recovery for App-Bound rows in browsers without native extraction
- explain missing browsers, missing profiles and ambiguous profile selection with next steps
- add windowsNative/resolveBrowserInfo, the operagx alias and sorted failure reasons in CLI output
- cover the Node server runtime with a real-DPAPI Windows test

* docs: document Windows Opera cookie import and guard browser lists against drift

* chore: file cookie-import follow-ups from the Opera fix wave review

* test: keep Opera receipt tests independent of the shared key cache

* test: declare generated gstack/llms.txt as a command-reference input for PR selection

* chore: release v1.91.4.0

* test: reconstruct the historical cookie-workflow approval after the Opera BROWSER.md additions

* test: run the real-DPAPI Windows check with the runner's environment

PowerShell launched with a stripped environment took ~18-21s on the Windows
runner (measured on a throwaway diagnostics run), past dpapiDecrypt's 10s
deadline; with the full environment it returns in ~0.3s. Only APPDATA is
redirected to the fixture's Opera root.

---------

Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>

ARCHITECTURE.md

@@ -199,7 +199,7 @@ Storage reset and authentication verification are independent opt-ins. `--clear-
 
 ### Shell injection prevention
 
-The browser registry (Chrome, Chromium, Brave, Edge, and macOS-only Comet, Arc, Dia) is hardcoded. Database roots come from known platform locations; profile directory input is validated. Keychain access uses `Bun.spawn()` with explicit argument arrays, not shell string interpolation.
+The browser registry (Chrome, Chromium, Brave, Edge, Windows-only Opera and Opera GX, and macOS-only Comet, Arc, Dia) is hardcoded. Database roots come from known platform locations; profile directory input is validated. Keychain access uses `Bun.spawn()` with explicit argument arrays, not shell string interpolation.
 
 ### Egress receipt ledger (v1.63.0.0)