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-add-feature/SKILL.md

@@ -0,0 +1,44 @@
+---
+name: orch-add-feature
+description: Orchestrate building a brand-new feature end to end — research, plan, TDD implementation, review, and gated commit — by delegating each phase to the matching ECC agent. Use when adding a capability that does not exist yet.
+origin: ECC
+---
+
+# orch-add-feature
+
+Actor · action · target: **orch · add · feature**. Thin wrapper over the shared
+engine in [`orch-pipeline`](../orch-pipeline/SKILL.md).
+
+## When to Use
+
+- The user wants a capability that does **not exist yet** ("add", "build",
+  "implement", "support …").
+- It is net-new behavior — not a correction (`orch-fix-defect`) and not an
+  alteration of existing behavior (`orch-change-feature`).
+
+## Operation settings
+
+- **Default size floor:** standard — run Research + Plan unless clearly small.
+- **Phase mask:** 0 → 1 → 2 → 4 → 5 → 6 (skip 3 Scaffold; that is MVP-only).
+- **First move (phase 4):** write *new* failing tests for the new behavior, then
+  implement to green.
+
+## How It Works
+
+1. Run the `orch-pipeline` engine with the settings above.
+2. Classify size first; small / trivial features collapse toward 4 → 5 → 6.
+3. Stop at **Gate 1** (plan approval) and **Gate 2** (pre-commit).
+4. Add `security-reviewer` if the feature touches a security trigger.
+
+> Related: `/feature-dev` is a standalone version of this flow. `orch-add-feature`
+> differs by sharing the `orch-pipeline` engine — the size classifier and the two
+> gates — with the rest of the family, so it right-sizes trivial features to 4 → 5 → 6.
+
+## Example
+
+```
+orch-add-feature: add OAuth2 login to nws-poller
+→ research existing auth libs → plan task_list  [GATE 1: approve]
+→ TDD each task → code-review (+ security-reviewer: auth path)
+→ commit  [GATE 2: confirm]
+```