fix(test): context-restore gets a private home — the REAL root cause was fixture sharing

The evidence-based assertion fix was treating a symptom. The slice
artifact's embedded transcript showed the CI agent restoring
20260829-context-save-skill-test.md — the checkpoint the SIBLING
context-save test wrote into the SHARED gstackHome checkpoints dir,
which by filename-prefix ordering genuinely IS the newest. The agent
behaved CORRECTLY; the test's fixture set was open to concurrent
sibling writes, and bun --concurrent ordering differs between CI (save
finished first) and local (restore listed first) — the entire
local-green/CI-red split explained.

The restore test now uses its own .gstack-restore-home (the whole home
moves, not just the handed path — an agent deriving the dir from
GSTACK_HOME/projects/<slug> must land in the closed set too). Full file
4/4 paid green with all evidence flags firing.

Also: the on-failure shard-log artifact glob uploaded nothing — the
Fix-bun-temp step points TMPDIR at /home/runner/.cache, so the spool
lands there, not /tmp. Both eval workflows now glob both locations
(this gap is why diagnosing THIS failure required digging transcripts
out of the slice-results artifact).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/evals-periodic.yml

@@ -239,7 +239,12 @@ jobs:
         uses: actions/upload-artifact@v7
         with:
           name: paid-slice-${{ matrix.slice }}-logs
-          path: /tmp/gstack-paid-shard-*.log
+          # The Fix-bun-temp step points TMPDIR at /home/runner/.cache, so the
+          # runner's spool lands THERE, not /tmp — the original /tmp glob
+          # uploaded nothing and a red slice's diagnostics were unreachable.
+          path: |
+            /home/runner/.cache/gstack-paid-shard-*.log
+            /tmp/gstack-paid-shard-*.log
           if-no-files-found: ignore
           retention-days: 30
 

.github/workflows/evals.yml

@@ -675,7 +675,12 @@ jobs:
         uses: actions/upload-artifact@v7
         with:
           name: paid-slice-${{ matrix.slice }}-logs
-          path: /tmp/gstack-paid-shard-*.log
+          # The Fix-bun-temp step points TMPDIR at /home/runner/.cache, so the
+          # runner's spool lands THERE, not /tmp — the original /tmp glob
+          # uploaded nothing and a red slice's diagnostics were unreachable.
+          path: |
+            /home/runner/.cache/gstack-paid-shard-*.log
+            /tmp/gstack-paid-shard-*.log
           if-no-files-found: ignore
           retention-days: 30
 

test/skill-e2e-session-intelligence.test.ts

@@ -274,7 +274,17 @@ IMPORTANT:
   // claude -p. Verify the agent identifies the newer file (by filename prefix)
   // and presents its content, regardless of the current branch.
   testConcurrentIfSelected('context-restore-loads-latest', async () => {
-    const projectDir = path.join(gstackHome, 'projects', slug);
+    // PRIVATE home for this test: the suite runs concurrently, and the shared
+    // gstackHome's checkpoints dir also receives the context-save test's
+    // freshly-written checkpoint (a 2026-08-29 filename prefix — always the
+    // "newest"). In CI, save completed before this test's agent listed the
+    // dir, so the agent CORRECTLY restored the sibling's checkpoint and the
+    // assertions failed; locally the ordering happened to run restore first.
+    // An isolated home makes the fixture set closed regardless of ordering
+    // (the agent may derive the dir from GSTACK_HOME/projects/<slug>, so the
+    // whole home moves, not just the checkpoint path we hand it).
+    const restoreHome = path.join(workDir, '.gstack-restore-home');
+    const projectDir = path.join(restoreHome, 'projects', slug);
     const checkpointDir = path.join(projectDir, 'checkpoints');
     fs.mkdirSync(checkpointDir, { recursive: true });
 
@@ -333,7 +343,7 @@ This is the newest saved context. Cross-branch restore should load THIS file.
 ${restoreSection.slice(0, 2500)}
 
 IMPORTANT:
-- Use GSTACK_HOME="${gstackHome}" as an environment variable when running bin scripts.
+- Use GSTACK_HOME="${restoreHome}" as an environment variable when running bin scripts.
 - The bin scripts are at ./bin/ (relative to this directory), not at ~/.claude/skills/gstack/bin/.
 - Look in ${checkpointDir} for saved context files.
 - Current branch is "main" — do NOT filter by current branch. Load across all branches.