feat: worktree isolation for E2E tests + infrastructure elegance (v0.11.12.0) (#425)

* refactor: extract gen-skill-docs into modular resolver architecture

Break the 3000-line monolith into 10 domain modules under scripts/resolvers/:
types, constants, preamble, utility, browse, design, testing, review,
codex-helpers, and index. Each module owns one domain of template generation.

The preamble module introduces a 4-tier composition system (T1-T4) so skills
only pay for the preamble sections they actually need, reducing token usage
for lightweight skills by ~40%.

Adds a token budget dashboard that prints after every generation run showing
per-skill and total token counts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: tiered preamble — skills only pay for what they use

Tag all 23 templates with preamble-tier (T1-T4). Lightweight skills
like /browse and /benchmark get a minimal preamble (~40% fewer tokens),
while review skills get the full stack. Regenerate all SKILL.md files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: migrate eval storage to project-scoped paths

Move eval results and E2E run artifacts from ~/.gstack-dev/evals/ to
~/.gstack/projects/$SLUG/evals/ so each project's eval history lives
alongside its other gstack data. Falls back to legacy path if slug
detection fails.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: sync package.json version with VERSION after merge

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add WorktreeManager for isolated test environments

Reusable platform module (lib/worktree.ts) that creates git worktrees
for test isolation and harvests useful changes as patches. Includes
SHA-256 dedup, original SHA tracking for committed change detection,
and automatic gitignored artifact copying (.agents/, browse/dist/).

12 unit tests covering lifecycle, harvest, dedup, and error handling.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: integrate worktree isolation into E2E test infrastructure

Add createTestWorktree(), harvestAndCleanup(), and describeWithWorktree()
helpers to e2e-helpers.ts. Add harvest field to EvalTestEntry for
eval-store integration. Register lib/worktree.ts as a global touchfile.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: run Gemini and Codex E2E tests in worktrees

Switch both test suites from cwd: ROOT to worktree isolation.
Gemini (--yolo) no longer pollutes the working tree. Codex
(read-only) gets worktree for consistency. Useful changes are
harvested as patches for cherry-picking.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: skip symlinks in copyDirSync to prevent infinite recursion

Adversarial review caught that .claude/skills/gstack may be a symlink
back to the repo root, causing copyDirSync to recurse infinitely
when copying gitignored artifacts into worktrees.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* chore: bump version and changelog (v0.11.12.0)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: relax session-awareness assertion to accept structured options

The LLM consistently presents well-formatted A/B choices with pros/cons
but doesn't always use the exact string "RECOMMENDATION". Accept
case-insensitive "recommend", "option a", "which do you want", or
"which approach" as equivalent signals of a structured recommendation.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

test/gemini-e2e.test.ts

@@ -13,11 +13,12 @@
  * Skips gracefully when prerequisites are not met.
  */
 
-import { describe, test, expect, afterAll } from 'bun:test';
+import { describe, test, expect, beforeAll, afterAll } from 'bun:test';
 import { runGeminiSkill } from './helpers/gemini-session-runner';
 import type { GeminiResult } from './helpers/gemini-session-runner';
 import { EvalCollector } from './helpers/eval-store';
 import { selectTests, detectBaseBranch, getChangedFiles, GLOBAL_TOUCHFILES } from './helpers/touchfiles';
+import { createTestWorktree, harvestAndCleanup } from './helpers/e2e-helpers';
 import * as path from 'path';
 
 const ROOT = path.resolve(import.meta.dir, '..');
@@ -114,13 +115,22 @@ afterAll(async () => {
 // --- Tests ---
 
 describeGemini('Gemini E2E', () => {
+  let testWorktree: string;
+
+  beforeAll(() => {
+    testWorktree = createTestWorktree('gemini');
+  });
+
+  afterAll(() => {
+    harvestAndCleanup('gemini');
+  });
 
   testIfSelected('gemini-discover-skill', async () => {
-    // Run Gemini in the repo root where .agents/skills/ exists
+    // Run Gemini in an isolated worktree (has .agents/skills/ copied from ROOT)
     const result = await runGeminiSkill({
       prompt: 'List any skills or instructions you have available. Just list the names.',
       timeoutMs: 60_000,
-      cwd: ROOT,
+      cwd: testWorktree,
     });
 
     logGeminiCost('gemini-discover-skill', result);
@@ -139,11 +149,11 @@ describeGemini('Gemini E2E', () => {
   }, 120_000);
 
   testIfSelected('gemini-review-findings', async () => {
-    // Run gstack-review skill via Gemini on this repo
+    // Run gstack-review skill via Gemini on worktree (isolated from main working tree)
     const result = await runGeminiSkill({
       prompt: 'Run the gstack-review skill on this repository. Review the current branch diff and report your findings.',
       timeoutMs: 540_000,
-      cwd: ROOT,
+      cwd: testWorktree,
     });
 
     logGeminiCost('gemini-review-findings', result);