fix: CRLF frontmatter parsing, duplicate cwd crash, STATE.md phase transitions (#1105)

- fix(frontmatter): handle CRLF line endings in extractFrontmatter,
  spliceFrontmatter, and parseMustHavesBlock — fixes wave parsing on
  Windows where all plans reported as wave 1 (#1085)

- fix(hooks): remove duplicate const cwd declaration in
  gsd-context-monitor.js that caused SyntaxError on every PostToolUse
  invocation (#1091, #1092, #1094)

- feat(state): add 'state begin-phase' command that updates STATUS,
  Last Activity, Current focus, Current Position, and plan counts
  when a new phase starts executing (#1102, #1103, #1104)

- docs(workflow): add state begin-phase call to execute-phase workflow
  validate_phase step so STATE.md is current from the start

get-shit-done/workflows/execute-phase.md

@@ -54,6 +54,12 @@ All subsequent commits go to this branch. User handles merging.
 From init JSON: `phase_dir`, `plan_count`, `incomplete_count`.
 
 Report: "Found {plan_count} plans in {phase_dir} ({incomplete_count} incomplete)"
+
+**Update STATE.md for phase start:**
+```bash
+node "$HOME/.claude/get-shit-done/bin/gsd-tools.cjs" state begin-phase --phase "${PHASE_NUMBER}" --name "${PHASE_NAME}" --plans "${PLAN_COUNT}"
+```
+This updates Status, Last Activity, Current focus, Current Position, and plan counts in STATE.md so frontmatter and body text reflect the active phase immediately.
 </step>
 
 <step name="discover_and_group_plans">