test: add gate-tier mode-posture regression tests

Three gate-tier E2E tests detect when preamble / template changes
flatten the distinctive posture of /plan-ceo-review SCOPE EXPANSION or
/office-hours (startup Q3, builder mode). The V1 regression that this
PR fixes shipped without anyone catching it at ship time — this is the
ongoing signal so the same thing doesn't happen again.

Pieces:
- `judgePosture(mode, text)` in `test/helpers/llm-judge.ts`. Sonnet
  judge with mode-specific dual-axis rubric (expansion: surface_framing
  + decision_preservation; forcing: stacking_preserved +
  domain_matched_consequence; builder: unexpected_combinations +
  excitement_over_optimization). Pass threshold 4/5 on both axes.
- Three fixtures in `test/fixtures/mode-posture/` — deterministic input
  for expansion proposal generation, Q3 forcing question, and builder
  adjacent-unlock riffing.
- `plan-ceo-review-expansion-energy` case appended to
  `test/skill-e2e-plan.test.ts`. Generator: Opus (skill default). Judge:
  Sonnet.
- New `test/skill-e2e-office-hours.test.ts` with
  `office-hours-forcing-energy` + `office-hours-builder-wildness`
  cases. Generator: Sonnet. Judge: Sonnet.
- Touchfile registration in `test/helpers/touchfiles.ts` — all three as
  `gate` tier in `E2E_TIERS`, triggered by changes to
  `scripts/resolvers/preamble.ts`, the relevant skill template, the
  judge helper, or any mode-posture fixture.

Cost: ~$0.50-$1.50 per triggered PR. Sonnet judge is cheap; Opus
generator for the plan-ceo-review case dominates.

Known V1.1 tradeoff: judges test prose markers more than deep behavior.
V1.2 candidate is a cross-provider (Codex) adversarial judge on the
same output to decouple house-style bias.

test/fixtures/mode-posture/builder-idea.md

@@ -0,0 +1,15 @@
+# Weekend Project: Dependency Graph Visualizer
+
+I want to build a tool that takes a codebase and visualizes its dependency graph — modules, imports, which files depend on which. For fun, for learning. Maybe open-source it.
+
+## What I have so far
+
+- Rough idea: point it at a repo, get an interactive graph
+- Stack I'm leaning toward: TypeScript + D3 or Cytoscape for rendering
+- Potential: could work for JS/TS first, maybe Python later
+
+## What I don't know yet
+
+- How to make the visualization actually useful vs just pretty
+- Whether this should be a CLI, a web tool, or a VS Code extension
+- What would make someone else want to use it