chore(standards): all 17 branches to 100% — Windows-compat sweep + checker getattr fix

Windows-compat hardening across every branch to reach 100% on the seedgo
standards audit:
- UTF-8 stdout/stderr reconfigure guards (getattr form) on Rich/CLI entry points
- platform-branched POSIX-only subprocess kwargs (start_new_session ->
  CREATE_NEW_PROCESS_GROUP on win32)
- seedgo windows_compat checker: credit the getattr reconfigure form + locking test
- commons: shared-init test-suite speedup
- spawn: aipass_framework template — strip pytest.ini inline comments + add scaffold smoke test
- includes in-progress cross-OS testing work (doctor/init_flow/cross_os handlers + tests)

Verified: full audit 17/17 at 100%, pyright clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013uzDhtcZ6wT1T9e2AHPQig

src/aipass/cli/apps/cli.py

@@ -291,6 +291,10 @@ def main() -> int:
 
 
 if __name__ == "__main__":
+    if hasattr(sys.stdout, "reconfigure"):
+        sys.stdout.reconfigure(encoding="utf-8")  # type: ignore[attr-defined]
+    if hasattr(sys.stderr, "reconfigure"):
+        sys.stderr.reconfigure(encoding="utf-8")  # type: ignore[attr-defined]
     try:
         sys.exit(main())
     except KeyboardInterrupt: