[codex] Add platform ledger foundation

[cody257]

Summary

• Add the AppLens platform ledger foundation with append-only JSONL events and a SQLite query index.
• Add module discovery/status plumbing for AppLens-LLM, Oracle, Mailbox, and Zero roots via environment variables.
• Add Tune action execution scaffolding, including startup toggle support and explicit consent/future-action blocking.
• Surface the platform ledger in the desktop shell and cover the backend services with focused tests.

Validation

• Staged-only temp worktree verification.
• dotnet test AppLensDesktop.sln: 40 passed, 0 failed.
• dotnet build AppLensDesktop.sln: succeeded with 0 warnings and 0 errors.
• git diff --cached --check: passed.

Notes

• This does not merge to main.
• Unrelated local dirty files were intentionally left unstaged.