fix: resolve issue cluster (#2295,#2298,#2303,#2304,#2305,#2306,#2340) + createdTime fallback bug

- session-manager: fix createdTime birthtime||ctime fallback that never fired
  (a Date is always truthy); use birthtimeMs>0 check via resolveCreatedTime()
- installer: rewrite source-relative rules/skills links for the injected
  ecc/ namespace so installed skills resolve correctly (#2340)
- continuous-learning-v2: drop unused mock import (#2305); standardize bash
  shebangs (#2303); poll for PID file instead of fixed sleep (#2295);
  rename _ecc_* -> _clv2_* (#2304); align promotion confidence docs (#2298);
  de-brittle Scope Decision Guide cross-reference (#2306)

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

tests/hooks/observer-memory.test.js

@@ -375,7 +375,7 @@ test('observe.sh creates counter file and increments on each call', () => {
     path.join(scriptsLibDir, 'homunculus-dir.sh'),
     [
       '#!/bin/bash',
-      '_ecc_resolve_homunculus_dir() { printf "%s\\n" "$HOME/.local/share/ecc-homunculus"; }',
+      '_clv2_resolve_homunculus_dir() { printf "%s\\n" "$HOME/.local/share/ecc-homunculus"; }',
       ''
     ].join('\n')
   );