fix: harden CI validators, shell scripts, and expand test suite

- Add try-catch around readFileSync in validate-agents, validate-commands,
  validate-skills to handle TOCTOU races and file read errors
- Add validate-hooks.js and all test suites to package.json test script
  (was only running 4/5 validators and 0/4 test files)
- Fix shell variable injection in observe.sh: use os.environ instead of
  interpolating $timestamp/$OBSERVATIONS_FILE into Python string literals
- Fix $? always being 0 in start-observer.sh: capture exit code before
  conditional since `if !` inverts the status
- Add OLD_VERSION validation in release.sh and use pipe delimiter in sed
  to avoid issues with slash-containing values
- Add jq dependency check in evaluate-session.sh before parsing config
- Sync .cursor/ copies of all modified shell scripts

.cursor/skills/continuous-learning-v2/agents/start-observer.sh

@@ -88,10 +88,12 @@ case "${1:-start}" in
         # Use Claude Code with Haiku to analyze observations
         # This spawns a quick analysis session
         if command -v claude &> /dev/null; then
-          if ! claude --model haiku --max-turns 3 --print \
+          exit_code=0
+          claude --model haiku --max-turns 3 --print \
             "Read $OBSERVATIONS_FILE and identify patterns. If you find 3+ occurrences of the same pattern, create an instinct file in $CONFIG_DIR/instincts/personal/ following the format in the observer agent spec. Be conservative - only create instincts for clear patterns." \
-            >> "$LOG_FILE" 2>&1; then
-            echo "[$(date)] Claude analysis failed (exit $?)" >> "$LOG_FILE"
+            >> "$LOG_FILE" 2>&1 || exit_code=$?
+          if [ "$exit_code" -ne 0 ]; then
+            echo "[$(date)] Claude analysis failed (exit $exit_code)" >> "$LOG_FILE"
           fi
         else
           echo "[$(date)] claude CLI not found, skipping analysis" >> "$LOG_FILE"