Refactor: Move timestamp function to shared helpers (DRY cleanup)

ISSUE:
- get_local_timestamp() was defined in main script
- Function was not reusable by other scripts
- Violated DRY principles (duplication risk)

ROOT CAUSE:
- Function was created before common-helpers.sh existed
- Never migrated to shared library

FIX:
- Added timestamp_local() to dist/bin/lib/common-helpers.sh
- Replaced 2 calls to get_local_timestamp() with timestamp_local()
  * Line 414: Log header timestamp
  * Line 463: Log footer timestamp
- Deleted duplicate function definition from main script (line 234-236)

IMPACT:
- Timestamp function now reusable across all scripts
- Follows DRY principles (single source of truth)
- Future scripts can use timestamp_local() without duplication
- Zero functional changes (output format unchanged)

TESTING:
- Ran script and verified log timestamps still work correctly
- Format: 2025-12-31 11:32:06 PST ✓
- Appears in both log header and footer ✓

RELATED:
- Part of DRY cleanup initiative (Phase 2)
- Complements Phase 1 version drift fix

Author: noelsaw1

CHANGELOG.md

@@ -20,6 +20,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
     - Line 1216: Banner version (now uses `$SCRIPT_VERSION`)
   - **Future-Proof:** Only need to update ONE line (line 50) when bumping versions
 
+- **Duplicate Timestamp Function** - Removed duplicate `get_local_timestamp()` and moved to shared helpers
+  - **Issue:** `get_local_timestamp()` was defined in main script instead of using shared helper library
+  - **Root Cause:** Function was created before `common-helpers.sh` existed
+  - **Fix:**
+    - Added `timestamp_local()` to `dist/bin/lib/common-helpers.sh` (line 23-28)
+    - Replaced 2 calls to `get_local_timestamp()` with `timestamp_local()` (lines 414, 463)
+    - Deleted duplicate function definition from main script
+  - **Impact:** Timestamp function now reusable across all scripts, follows DRY principles
+  - **Benefit:** Future scripts can use `timestamp_local()` without duplicating code
+
 - **Template Loading Path** - Fixed `REPO_ROOT` variable in bash script to correctly load templates from `dist/TEMPLATES/`
   - **Issue:** Script was looking for templates in repository root `/TEMPLATES/` instead of `dist/TEMPLATES/`
   - **Root Cause:** `REPO_ROOT` was set to `$SCRIPT_DIR/../..` (repository root) instead of `$SCRIPT_DIR/..` (dist directory)

dist/bin/check-performance.sh

@@ -231,10 +231,6 @@ count_lines_of_code() {
 }
 
 # Get local timestamp for user-friendly display
-get_local_timestamp() {
-  date +"%Y-%m-%d %H:%M:%S %Z"
-}
-
 # Detect WordPress plugin or theme information
 # Returns JSON object with project metadata including file/LOC counts
 detect_project_info() {
@@ -411,7 +407,7 @@ if [ "$ENABLE_LOGGING" = true ]; then
       fi
 
       echo "Generated (UTC):  $(date -u +"%Y-%m-%d %H:%M:%S")"
-      echo "Local Time:      $(get_local_timestamp)"
+      echo "Local Time:      $(timestamp_local)"
         echo "Script Version:   $SCRIPT_VERSION"
       echo "Paths Scanned:    $PATHS"
       echo "Strict Mode:      $STRICT"
@@ -460,7 +456,7 @@ log_exit() {
       echo ""
       echo "========================================================================"
       echo "Completed (UTC): $(date -u +"%Y-%m-%d %H:%M:%S")"
-      echo "Local Time:     $(get_local_timestamp)"
+      echo "Local Time:     $(timestamp_local)"
       echo "Exit Code:      $exit_code"
       echo "========================================================================"
     } >> "$LOG_FILE"

dist/bin/lib/common-helpers.sh

@@ -19,3 +19,10 @@ timestamp_filename() {
 timestamp_iso8601() {
   date -u +"%Y-%m-%dT%H:%M:%SZ"
 }
+
+# Generate local timestamp with timezone for display/logs
+# Usage: timestamp_local
+# Returns: 2025-12-31 11:27:32 PST
+timestamp_local() {
+  date +"%Y-%m-%d %H:%M:%S %Z"
+}