fix(#2128): bound the phase-tag clause to {0,200} — kill quadratic ReDoS

The canonical OPTIONAL_PHASE_TAG_SOURCE tag clause `(?:\s*\([^)\n]*\))?` (and its
inlined literal mirrors across 11 modules) had an UNBOUNDED body, making the
optional-group + /g header scan quadratic on adversarial ROADMAP.md/STATE.md — a
long run of `(` after a header ran ~18.8s at 1.7MB. Bound the body to {0,200} in
the constant AND every mirror in lockstep (the #1729 "both forms change together"
contract), so the scan is linear: the same 1.7MB input now resolves in ~9ms
(measured), while real tags (a handful of chars) still match and a 201-char tag
is rejected. Added a #2128 boundary regression to the #1729 suite.

Pre-existing (byte-identical before/after the Phase 4 migrations); folded in at
maintainer direction rather than deferred.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/roadmap.cts

@@ -297,9 +297,9 @@ function cmdRoadmapAnalyze(cwd: string, raw: boolean): void {
   const phasesDir = planningPaths(cwd).phases;
 
   // Extract all phase headings: ## Phase N: Name or ### Phase N: Name
-  // #1729: `(?:\s*\([^)\n]*\))?` tolerates a pre-colon ( ) tag (literal mirror of OPTIONAL_PHASE_TAG_SOURCE).
+  // #1729: `(?:\s*\([^)\n]{0,200}\))?` tolerates a pre-colon ( ) tag (literal mirror of OPTIONAL_PHASE_TAG_SOURCE).
   // phase-id-owner: uses the [.-] (dot-or-dash) separator variant, not the canonical dot-only token; a swap to PHASE_NUMBER_TOKEN_SOURCE would drop hyphenated phase-id matches.
-  const phasePattern = /#{2,4}\s*(?:\[[^\]]+\]\s*)?Phase\s+(\d+[A-Z]?(?:[.-]\d+)*)(?:\s*\([^)\n]*\))?\s*:\s*([^\n]+)/gi;
+  const phasePattern = /#{2,4}\s*(?:\[[^\]]+\]\s*)?Phase\s+(\d+[A-Z]?(?:[.-]\d+)*)(?:\s*\([^)\n]{0,200}\))?\s*:\s*([^\n]+)/gi;
   const phases: Array<{
     number: string;
     name: string;