fix(push): stop offering a teammate's update back as a local edit (#823)

[SaulMoro]

Summary

Push could still list a copy the member never edited as modified, ready to send a teammate's update back as the old version. This fixes three of the paths #823 lists.

where push decides "did the member edit this copy?"
├── pre-push sync (git show)   single-repo mode     ── 2. path never resolved
├── placed agents              base                 ── 3. shared lastPullRev
└── pre-push sync skill copy   fails partway        ── 5. two revisions mixed

 syncTeamUpdatesToLocal(bases)                        # pre-push-sync.ts
-  git show <rev>:rules/x.md                          # single-repo: resolved from repo root, never found
+  git show <rev>:./rules/x.md                        # resolved from <wt>/.teamai
   skill at a base
-    copyDir(team, local)                             # overwrites in place
+    stage = copy(local) + copyDir(team)              # hidden sibling
+    rename local -> prev, stage -> local, rm prev    # a failure leaves the old copy whole

 AgentsHandler.scanLocalForPush                       # agents.ts
-  recordedAgentMovedOn(lastPullRev)
+  recordedAgentMovedOn(checkoutBaseRevs(record) or [lastPullRev])
+    held if the team file differs from its version at any base,
+    or from the version it was added with when a base predates it

Before / After (real CLI, teamai --dry-run push):

Scenario	Before (origin/main f558b94)	After
Item 2: single-repo, teammate updated .teamai/rules/team-rule.md, no teamai pull	[rules] team-rule (modified)	synced to the teammate's version, nothing to push
Item 3: placed agent, stale worktree, only the main checkout pulled the rewrite	[agents] vr (modified)	Skipped vr: ... changed on the team since this checkout last synced it

Type of Change

• Bug fix (non-breaking change that fixes an issue)

Causes:

• Item 2. Single-repo push runs with repo.localPath = <knowledge-wt>/.teamai, and git show resolves paths from the repo root, so no base was ever found.
• Item 3. The shared lastPullRev is moved by a pull in another checkout (the [bug] push from a stale worktree diffs against another checkout's revision and can revert a teammate's update #812 revert, for agents). Push bases mark where rules and skills were synced, not agents, so any differing base counts. Push records the team HEAD before the scan, so the added-with version is also compared when a base predates the placement.
• Item 5. A partial in-place copy mixed two revisions, which match no base. The stage starts from the local copy, so files only the member has survive as before.

Test Plan

• npx tsc --noEmit passes
• npx vitest run passes: 316 files, 4964 passed, 1 skipped
• Added/updated tests for the change

New tests, all red on origin/main (f558b94) or under ablation:

e2e push-sync-followups-823
  item 2  teammate lands R2, branch fast-forwarded, no teamai pull -> synced, not listed   red on main
  item 2  genuine local edit -> still listed
  item 3  worktree B at R1, only main pulled R2 -> held in B                               red on main
  item 3  pull, place, merge, teammate edits, no pull -> held        guards the added-with fallback
unit    copyDir writes one file, throws ENOSPC -> skill whole, nothing beside it          red on main
unit    member-only files kept; read-only skill left whole, no leftover

Ablations, repeated after the rebase onto 21cb76a: each change was reverted alone and its test failed at the expected assertion. That covers the ./ prefix, agents.ts, the added-with fallback, the staged copy and the cleanup chmod. Three assertions in pre-push-sync.test.ts pinned the buggy argument rules/..., and now say ./rules/....

Build/Result: npm run build ok. E2E run (--retry 0): the new file, plus push-stale-worktree-812, push-namespace-e2e, role-scoped-agents, namespaced-entries, project-agent-cold-start, e2e, multi-project and copilot-agents: 9 files, 84 passed, 22 skipped (the skipped ones need a remote). The full e2e suite was not run.

Real CLI, before (origin/main f558b94) and after (this branch)

=== item 2, single-repo mode (before) ===
  .claude/rules/team-rule.md after pull: Version one.
  teammate pushed R2; member's branch fast-forwarded with git, no teamai pull
  $ teamai --dry-run push
    Found 1 resource(s) to push:
        1. [rules] team-rule (modified)
  .claude/rules/team-rule.md after push: Version one.

=== item 3, placed agent in a stale worktree (before) ===
    ✔ Pushed branch teamai/push/ci-823/...        (push --project front-app, then merged)
  wt-b agent after pull: You review.
  teammate rewrote vr; only the main checkout pulled it
  $ (wt-b) teamai --dry-run push
    Found 1 resource(s) to push:
        1. [agents] vr (modified)
           to:   agents/fe-agents/vr.yaml

=== item 2, single-repo mode (after) ===
  $ teamai --dry-run push
    ℹ No new or modified resources to push
  .claude/rules/team-rule.md after push: Version two, from a teammate.

=== item 3, placed agent in a stale worktree (after) ===
  $ (wt-b) teamai --dry-run push
    ⚠ [agents] Skipped vr: Agent "vr" (agents/fe-agents/vr.yaml) changed on the team since this checkout last synced it, ...
    ℹ No new or modified resources to push

Provider git (local bare remote), agent Claude. Other providers and agents are left to CI.

Related Issues

Part of #823 (items 2, 3 and 5; item 4 follows once #814 is merged)

Notes for Reviewers

Reproduced with the real CLI: items 2 and 3 (above).

From reading the code, covered by unit tests only: item 5. The partial-copy failure is forced by a mocked copyDir, plus a real read-only skill.

• The hold message changes from "this machine" to "this checkout". The usage guides (en/zh) and the design doc follow.
• The docs touched are also in fix(data-layout): let every self-mode worktree publish learnings and keep its queue (#808) #814's file list, but not the passages it edits. git merge-tree of this branch with fix(data-layout): let every self-mode worktree publish learnings and keep its queue (#808) #814's head (628f797) reports only the conflicts fix(data-layout): let every self-mode worktree publish learnings and keep its queue (#808) #814 already has with main (CHANGELOG.md, src/contribute.ts, src/recall.ts), none from this branch.
• Rebased onto 21cb76a (feat(agents): support WorkBuddy subagent distribution #826, feat: one namespace model for every resource type (#707) #816). Under feat: one namespace model for every resource type (#707) #816 a placed agent also replaces a shared-root agent of its name, so more agents reach the placed-agent guard (candidates === recorded); the guard now compares them with this checkout's bases like the rest.
• Item 5 limits. Two directories cannot be swapped atomically. A kill between the renames leaves the previous version in a hidden .<skill>.<pid>.<hex>.teamai-prev; a failed restore names that path. A read-only subfolder can leave a leftover, and the warning names it.
• Out of scope, found while testing. In single-repo mode, the active tree's .teamai/rules is itself a scan source. A branch that has not merged a teammate's update lists its older copy as modified. That is why the item 2 test fast-forwards the branch. It is tracked in [bug] Follow-ups to the worktree fixes: import --from-mr never shares its learning, and push can still revert a teammate's update #823.
• Also tracked in [bug] Follow-ups to the worktree fixes: import --from-mr never shares its learning, and push can still revert a teammate's update #823, with item 4: one helper for the checkout bases, shared by push.ts and the agent guard (it belongs in pull.ts, which fix(data-layout): let every self-mode worktree publish learnings and keep its queue (#808) #814 changes).
• Two-way door. Blast radius: the pre-push sync and the placed-agent guard.

[github-actions]

No findings.

The PR description documents sufficient testing for this runtime change, including representative real-CLI verification. Per instruction, I reviewed only the specified diff and did not run or build the PR code.

[github-actions]

No findings.

The PR description documents sufficient testing for this runtime change, including representative real-CLI verification. I reviewed only the specified diff and did not run, build, or install the PR code.