feat: add orch-* orchestrator skill family (#2153)

* feat: add orch-* orchestrator skill family

Lightweight wrappers that orchestrate existing ECC agents through a gated Research -> Plan -> TDD -> Review -> Commit pipeline, right-sized per task.

- orch-pipeline: shared engine (phases, size classifier, two gates, agent map)
- orch-add-feature/change-feature/fix-defect/refine-code/build-mvp: thin wrappers delegating to the engine

* chore: register orch-* family in catalog, command registry, and agent.yaml (post-rebase onto green main)

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Co-authored-by: ECC Test <ecc@example.test>

skills/orch-fix-defect/SKILL.md

@@ -0,0 +1,42 @@
+---
+name: orch-fix-defect
+description: Orchestrate fixing a bug — reproduce it as a failing regression test, fix to green, review, and gated commit — by delegating each phase to the matching ECC agent. Use when existing behavior is broken or wrong.
+origin: ECC
+---
+
+# orch-fix-defect
+
+Actor · action · target: **orch · fix · defect**. Thin wrapper over the shared
+engine in [`orch-pipeline`](../orch-pipeline/SKILL.md).
+
+## When to Use
+
+- Something is **broken**: wrong output, an error, a crash, a regression.
+- Distinguish from siblings:
+  - behavior is correct but you want it different → `orch-change-feature`.
+  - the capability does not exist yet → `orch-add-feature`.
+
+## Operation settings
+
+- **Default size floor:** small (often trivial).
+- **Phase mask:** 0 → (light 2 only if root cause is non-obvious or standard+) →
+  4 → 5 → 6. Research (1) is usually skipped.
+- **First move (phase 4):** reproduce the bug as a **new failing** test
+  (regression test), then fix until it goes green. Proving the bug exists first
+  is what separates a fix from a tweak.
+
+## How It Works
+
+1. Run the `orch-pipeline` engine with the settings above.
+2. If the root cause is unclear, scope it with `code-explorer` before the red
+   test; escalate build breaks to `build-error-resolver` / `/build-fix`.
+3. Stop at **Gate 1** (only if a plan was produced) and **Gate 2** (pre-commit).
+4. Add `security-reviewer` if the defect sits in a security-sensitive path.
+
+## Example
+
+```
+orch-fix-defect: poller crashes on empty NWS response
+→ write failing test reproducing the crash → fix to green
+→ code-review → commit  [GATE 2: confirm]   (commit: fix:)
+```