Fixes 4 issues identified in PR #35 code review:
## 1. Self-Primary Identity Check (Copilot #1)
- BEFORE: `ctx.meId && (areJidsSameUser(...) || (ctx.meLid && ...))`
- AFTER: Check meId and meLid independently with OR
- FIX: Now correctly detects when only meLid exists
## 2. Debounce Cache Placement (Copilot #3, #4)
- BEFORE: Cache set immediately after debounce check
- AFTER: Cache set only before actual assertSessions call
- FIX: Prevents incorrect debouncing when exiting early (offline, etc.)
## 3. Session Regression (ChatGPT Codex P2)
- BEFORE: Returned 'skipped_no_session' when no session exists
- AFTER: Always call assertSessions - identity change IS the signal to rebuild
- FIX: Critical for key reset and device restore scenarios
## 4. Result Type Enhancement
- Added `hadExistingSession: boolean` to 'session_refreshed' result
- Removed 'skipped_no_session' action (no longer applicable)
- Enables better monitoring of session creation vs refresh
## Test Updates
- Added test for meLid-only self-primary detection
- Updated session creation test (no longer skips)
- Added test verifying debounce not set on offline skip
- Added Result Types test suite for type safety