PAPA-430: workspace finalize gates + no-remote-git enforcement (#6969)

## Thinking Path

> - Paperclip orchestrates AI agents across isolated execution
workspaces; the local cwd is the only persistence boundary between runs.
> - Workspace lifecycle (worktree_prepare → execute →
workspace_finalize) and the wake/accept flow are what guarantee that
dependent issues see a consistent worktree.
> - PAPA-380 / PAPA-431 / PAPA-432 / PAPA-440 surfaced three holes in
that contract: silent env reuse across assignees, dependent wakes firing
before finalize, and `issue.interaction.accept` advancing before
finalize landed.
> - PAPA-441 / PAPA-442 then needed to document the "no remote git"
contract and prevent future adapter/runtime code from quietly
reintroducing `git push` as a backdoor sync.
> - This pull request lands those server fixes, the static
`check-no-git-push` enforcement, the AUTHORING.md cross-link, and the
Cody-review follow-ups on the PAPA-430 thread.
> - The benefit is that finalize is a real barrier — board accepts,
dependent wakes, and operator-set env all respect it — and adapter code
can't bypass it via raw `git push`.

## What Changed

- **server (PAPA-380, PAPA-431):** `execution-workspace-policy` refuses
silent env reuse when the assignee's resolved env disagrees with the
workspace it would inherit. The inheritance protection is now scoped to
the actual inheritance signal — explicit issue-level `environmentId` is
honored even when the agent's default env is `null`.
- **server (PAPA-432):** `heartbeat.ts` gates dependent wakes on
`listUnfinalizedExecutionWorkspaceIds`, and writes a
`workspace_finalize` row on the succeeded path. Write failures now
surface instead of being swallowed so dependents aren't silently
stranded behind a missing row.
- **server (PAPA-440):** `issue-thread-interactions.acceptInteraction`
adds a workspace_finalize precondition for `request_confirmation` (not
`suggest_tasks`). Accept returns 409 if finalize hasn't succeeded for
the latest workspace operation.
- **ci (PAPA-442):** new `scripts/check-no-git-push.mjs` static check
scans `packages/adapters/`, `packages/adapter-utils/`, `server/src/`,
and `cli/src/` for any `git push` invocation (string or args-array).
Wired into the `policy` PR job and `test:release-registry`. Operators
can opt in per-call with `// paperclip:allow-git-push: <reason>`.
Release scripts are out of scope by design.
- **docs (PAPA-441):** `AUTHORING.md` documents the no-remote-git
contract and cross-links the static check so adapter authors learn the
rule and the enforcement together.
- **review follow-up (PAPA-430, Cody):** three fixes — env resolver bug,
accept-gate scope (request_confirmation only), and finalize record write
on the succeeded path.

## Verification

- `pnpm exec vitest run
server/src/__tests__/execution-workspace-policy.test.ts
server/src/__tests__/issue-thread-interactions-service.test.ts` → 33/33
pass
- `node scripts/check-no-git-push.test.mjs` → check covers string form,
args-array form, comment exclusions, and per-line allow-comment.
- Manual: server compiles; the policy job runs the check in <1s before
heavier jobs.

## Risks

- **Behavioral shift in accept:** boards accepting
`request_confirmation` while finalize is in-flight now get 409s. This is
intentional — they can retry — but it changes timing on a hot path.
`suggest_tasks` is unaffected.
- **Workspace policy:** the env-reuse refusal is a new error path.
Issues that previously silently reused an env from a different-assignee
workspace will now fail-loud; the resolver still honors explicit
issue-level `executionWorkspaceSettings.environmentId`.
- **CI rule:** any future legitimate `git push` in scoped dirs must be
marked with the allow-comment, which is the intended ergonomic.

## Model Used

- Claude Opus 4.7 (`claude-opus-4-7`, extended thinking), via Claude
Code in the Paperclip executor adapter.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [ ] If this change affects the UI, I have included before/after
screenshots (N/A — server/CI/docs only)
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

Closes related issues: PAPA-430, PAPA-380, PAPA-431, PAPA-432, PAPA-440,
PAPA-441, PAPA-442

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

docs/guides/board-operator/execution-workspaces-and-runtime-services.md

@@ -64,6 +64,17 @@ Heartbeat still resolves a workspace for the run, but that is about code locatio
 4. Heartbeat passes the resolved code workspace to the agent run.
 5. Workspace runtime services remain manual UI-managed controls rather than automatic heartbeat-managed services.
 
+## Cross-run persistence (no-remote-git contract)
+
+Code state moves between runs through the local execution-workspace cwd alone — not through a git remote.
+
+- Each run's prepare step bundles the local worktree to the run's remote dir over ssh, with no `git remote` configured.
+- The adapter's restore step at the end of the run writes any new remote commits back into the local worktree directly.
+- Adapters must never `git push` from runtime code, and must never assume a remote exists.
+- A failed restore is a run-level error and records `workspace_finalize=failed` on the execution workspace, which gates dependent issue wakes until the next successful finalize.
+
+The invariant is enforced by the "no-remote-git contract" case in `packages/adapter-utils/src/ssh-fixture.test.ts`, which asserts a remote-only commit reaches the local worktree with no remote configured at any point.
+
 ## Current implementation guarantees
 
 With the current implementation: