refactor(#1791): ADR-1769 Phase 6 — patch migration + curated current_phase_name preserve (#1695) (#1792)

Migrate cmdStatePatch (state.cts) onto the STATE.md Transition Module substrate
and close the curated-field clobber bug class #1743/#1695 (ADR-1769, epic #1769).

- Add {kind: 'patch'} to StateTransitionIntent, with patchCore in
  src/state-transition.cts. Applies each caller-supplied {field:value} pair via
  stateReplaceField over the full content (body + frontmatter), tracking
  updated vs. failed. data.updated/data.failed mirror the CLI output shape.
- Collapse cmdStatePatch to a transitionCore dispatch. Field-name validation
  (security) and the resync-progress decision stay in the adapter.
- #1695/#1743 fix: extend the #1230 delta heuristic in readModifyWriteStateMd to
  the curated current_phase_name, table-driven via
  getFieldClassification('current_phase_name').preservation === 'preserve-always'.
  When a write does NOT change the body Phase: source line, the curated
  frontmatter value wins over syncStateFrontmatter's body re-derivation (which
  harvests a wrong parenthetical aside — #1695). begin/planned/complete-phase
  rewrite their body Phase line, so the delta does not fire for them and
  current_phase_name still advances.
- Regression: bug-1695-state-patch-clobbers-phase-name.test.cjs — unrelated
  patch preserves curated current_phase_name; patching the Phase source advances.

All 70 transition + 493 regression tests pass (state/phase/milestone + #905/#397/#3242 lineages).

Closes #1791

scripts/lint-regression-test-names.allowlist.json

@@ -5,6 +5,7 @@
   "bug-1367-claude-local-flat-command-layout.test.cjs",
   "bug-14-progress-auto-flag-dropped.test.cjs",
   "bug-167-query-meta-command.test.cjs",
+  "bug-1695-state-patch-clobbers-phase-name.test.cjs",
   "bug-17-askuserquestion-option-cap.test.cjs",
   "bug-170-workflow-fallback-install-hint.test.cjs",
   "bug-1736-local-install-commands.test.cjs",

scripts/lint-test-file-count.allowlist.json

@@ -99,6 +99,7 @@
     },
     "state": {
       "files": [
+        "bug-1695-state-patch-clobbers-phase-name.test.cjs",
         "bug-21-state-md-template-frontmatter.test.cjs",
         "bug-2630-state-frontmatter-milestone-switch.test.cjs",
         "bug-3127-state-begin-phase-idempotent.test.cjs",