fix(#1196): wire discuss loop step for capability hooks (#1199)

* fix(#1196): wire discuss loop step for capability hooks

discuss was contract-declared (gsd:loop-host marker, in POINT_ORDER and
LOOP_HOST_CONTRACT) but structurally unwireable: discuss-phase.md had no
`loop render-hooks` dispatch and was absent from the conformance gate's
HOST_LOOP_FILES, so capabilities could never wire discuss:pre/discuss:post.

- discuss-phase.md: add minimal discuss:pre (before analyze_phase) and
  discuss:post (after write_context) render-hooks dispatch steps that
  delegate consumption to a new shared reference (kept under the 32KB
  #2551 budget; no inline subagent dispatch token).
- references/loop-hook-dispatch.md: new canonical, point-agnostic contract
  for consuming `loop render-hooks --raw` activeHooks (contribution/step/
  gate) — single source for hook consumption across host loops.
- gen-loop-host-contract.cjs: derive HOST_LOOP_FILES from STEP_WORKFLOWS and
  export scanWiredPoints()/getWiredLoopPoints() (throws on a missing host
  file) — one source of truth for the host-loop file + wired-point set.
- phase6-capstone-conformance.test.cjs: consume the derived HOST_LOOP_FILES
  and shared scanWiredPoints (was a hand-maintained duplicate omitting
  discuss-phase.md + a duplicated regex).
- gen-capability-registry.cjs: add validateHooksWired() gen-time guard that
  rejects a capability hook declared at a valid-but-unwired loop point, with
  a clear remediation message — failure now surfaces at gen --check/--write
  time instead of deep in the full conformance suite.
- tests (capability-registry.test.cjs): regression + anti-pattern parity
  guards (every loop-host marker is in STEP_WORKFLOWS/HOST_LOOP_FILES;
  POINT_ORDER === flattened LOOP_HOST_CONTRACT) so no step can drift into
  the discuss-class gap again.
- docs/INVENTORY*: register the new reference.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* chore(#1196): backfill changeset PR number (#1199)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/gen-loop-host-contract.cjs

@@ -449,6 +449,58 @@ function main() {
   }
 }
 
+// ─── Derived single-source-of-truth exports ───────────────────────────────────
+
+/**
+ * Repo-relative paths to every host-loop workflow file, derived from STEP_WORKFLOWS.
+ * This is the ONLY canonical enumeration of host-loop files — all consumers (tests,
+ * registry generator, conformance gate) must derive from this rather than maintaining
+ * a separate hardcoded list.
+ */
+const HOST_LOOP_FILES = STEP_WORKFLOWS.map((w) => 'gsd-core/workflows/' + w.file);
+
+/**
+ * Pure function: scan a text string for `loop render-hooks <point>` call sites.
+ * Returns a Set of matched point strings.
+ *
+ * @param {string} text  Content of a workflow file (or any text).
+ * @returns {Set<string>}
+ */
+function scanWiredPoints(text) {
+  const re = /loop render-hooks\s+([a-z:]+)/g;
+  const result = new Set();
+  let m;
+  while ((m = re.exec(text)) !== null) {
+    result.add(m[1]);
+  }
+  return result;
+}
+
+/**
+ * Read every host-loop workflow file and return the union of all wired loop points
+ * (i.e. points that have a `loop render-hooks <point>` call site).
+ *
+ * @param {string} [repoRoot]  Path to the repository root. Defaults to ROOT.
+ * @returns {Set<string>}
+ */
+function getWiredLoopPoints(repoRoot) {
+  const resolvedRoot = repoRoot !== undefined ? repoRoot : ROOT;
+  const result = new Set();
+  for (const relPath of HOST_LOOP_FILES) {
+    const absPath = path.join(resolvedRoot, relPath);
+    let content;
+    try {
+      content = fs.readFileSync(absPath, 'utf8');
+    } catch (err) {
+      throw new Error('getWiredLoopPoints: cannot read host-loop file ' + absPath + ': ' + err.message);
+    }
+    for (const point of scanWiredPoints(content)) {
+      result.add(point);
+    }
+  }
+  return result;
+}
+
 // ─── Exports (for tests) ─────────────────────────────────────────────────────
 
 module.exports = {
@@ -459,9 +511,12 @@ module.exports = {
   serializeContract,
   normalizeLineEndings,
   STEP_WORKFLOWS,
+  HOST_LOOP_FILES,
   CANONICAL_POINTS,
   EXPECTED_POINTS_BY_STEP,
   ROLE_TO_AGENT,
+  scanWiredPoints,
+  getWiredLoopPoints,
 };
 
 // ─── CLI entry point ──────────────────────────────────────────────────────────