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>

gsd-core/references/loop-hook-dispatch.md

@@ -0,0 +1,61 @@
+# Loop Hook Dispatch Contract
+
+Generic reference for consuming the `--raw` JSON output of `gsd_run loop render-hooks <point>`
+in any host-loop workflow. This document is point-agnostic — it applies to every loop
+extension point (discuss:pre, discuss:post, plan:pre, plan:post, execute:pre, execute:wave:pre,
+execute:wave:post, execute:post, verify:pre, verify:post, ship:pre, ship:post).
+
+## Envelope shape
+
+```json
+{
+  "point": "discuss:pre",
+  "activeHooks": [
+    { "kind": "contribution", "into": "orchestrator", "fragment": { "inline": "..." } },
+    { "kind": "step", "ref": { "skill": "my-skill" } },
+    { "kind": "gate", "check": { "query": "..." }, "blocking": true, "onError": "skip" }
+  ],
+  "rendered": "..."
+}
+```
+
+`activeHooks` is an array of enabled hook entries for the named point. It is empty (or absent)
+when no capability has registered an active hook at this point — treat that as a no-op.
+
+## Dispatch rules by `kind`
+
+### `contribution`
+
+Inject `fragment.inline` verbatim into the context for the role named in `into`
+(e.g. `orchestrator`, `planner`). Do not paraphrase — the text is the product.
+
+### `step`
+
+Dispatch the referenced unit:
+
+- `ref.skill` present → dispatch via the Skill tool with skill id `gsd-<ref.skill>`.
+- `ref.agent` present → dispatch via the Agent tool with `subagent_type` = `ref.agent`.
+  Before dispatching an agent, print the canonical liveness banner so users know silence
+  is expected and do not kill a healthy agent:
+
+  ```
+  ◆ Spawning <agent>... (runs in a subagent — no output until it returns; expected, not a freeze)
+  ```
+
+Wait for the result before continuing to the next hook or the next step.
+
+### `gate`
+
+Evaluate `check` (one of `query`, `predicate`, or `agentVerdict`). Then honor `blocking`:
+
+- `blocking: true` → if the check returns `block: true`, surface `check.message` to the user
+  and stop the current step. Do not continue.
+- `blocking: false` → advisory only; surface the message but continue regardless of outcome.
+
+Honor `onError` if the check itself errors: `skip` means treat as non-blocking and continue;
+`fail` means surface the error and stop.
+
+## Empty / absent `activeHooks`
+
+If `activeHooks` is absent, null, or an empty array, skip silently and continue to the next
+step in the workflow. No output to the user is needed.