feat(ultraplan-local): v1.8.0 — close Opus 4.7 schema-drift gap

Opus 4.7 reads agent instructions more literally than 4.6. The v1.7
planning-orchestrator described the Step+Manifest schema via prose +
procedural rules, which 4.6 inferred correctly but 4.7 sometimes
rendered as narrative "Fase N" prose — producing plans ultraexecute
Phase 2 rejected. First observed 2026-04-17 during llm-security v6.2.0
planning.

v1.8.0 closes the gap:

- planning-orchestrator Phase 5 embeds a literal copyable Step+Manifest
  example (JWT middleware) replacing "read the template" prose
- Explicit forbidden-format clause: ## Fase N, ### Phase N, ### Stage N,
  and any non-"### Step N:" heading are denied
- Phase 5.5 schema self-check: grep-verify canonical Step count matches
  Manifest count and narrative heading count is zero, before handing to
  plan-critic
- ultraexecute-local --validate mode: schema-only check that parses
  steps + manifests, reports READY/FAIL with actionable error hints,
  no security scan, no execution. Fast sanity check between
  /ultraplan-local and full execution.

Static verification: 17/17 PASS.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

plugins/ultraplan-local/CLAUDE.md

@@ -45,6 +45,7 @@ Flags can be combined: `--local --fg`, `--external --quick`.
 | _(default)_ | Execute plan — auto-detects Execution Strategy for multi-session |
 | `--resume` | Resume from last progress checkpoint |
 | `--dry-run` | Validate plan structure without executing |
+| `--validate` | Schema-only check — parse steps + manifests, report `READY \| FAIL`, no execution (v1.8) |
 | `--step N` | Execute only step N |
 | `--fg` | Force foreground — run all steps sequentially, ignore Execution Strategy |
 | `--session N` | Execute only session N from plan's Execution Strategy |