Add workspace PR rebase abilities

[chubes4]

Summary

• Adds low-level workspace git rebase and reset abilities, plus workspace_git_push support for guarded --force-with-lease pushes.
• Adds workspace_pr_rebase as the high-level bring-this-PR-home workflow, including drop-path conflict resolution, optional squash, and force-with-lease push.
• Adds workspace_pr_status plus chat/pipeline tool registration and CLI mappings for the new operations.

Closes #410.

Validation

• php tests/smoke-workspace-policy-tools.php passed.
• php tests/smoke-workspace-pr-rebase.php passed.
• homeboy lint data-machine-code --changed-since origin/main --summary passed with zero findings.
• homeboy test data-machine-code did not run tests: the Playground bootstrap failed while loading the data-machine dependency because WP_Agent_Principal_Access_Store was unavailable before DMC tests started.

Design notes

• drop_paths uses git checkout --ours during a rebase to keep the base branch version. That matches the issue's behavior contract to drop the PR version in favor of base; the literal --theirs spelling in the issue would keep the replayed PR-side change during a rebase.
• workspace_git_rebase returns state=conflicting with structured conflict files instead of raising a WP_Error when git reports merge conflicts, so agents can resolve and continue.
• workspace_git_push refuses force-with-lease pushes to common base branches and any configured fixed_branch; it never emits a bare force push.

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (gpt-5.5)
• Used for: Implemented the workspace git/PR ability plumbing, smoke tests, validation, and PR description. Chris remains responsible for review and merge.

[homeboy-ci]

Homeboy Results — data-machine-code

Lint

✅ lint — passed

ℹ️ Full options: homeboy docs commands/lint
ℹ️ Save lint baseline: homeboy lint data-machine-code --baseline
Deep dive: homeboy lint data-machine-code --changed-since 37c06d7

Test

❌ test — failed

ℹ️ No tests ran — the runner failed before producing results. See raw_output.stderr_tail / raw_output.stdout_tail for the underlying error (bootstrap failure, missing deps, DB connection, etc.).
ℹ️ To run specific tests: homeboy test data-machine-code -- --filter=TestName
ℹ️ Auto-fix lint issues: homeboy refactor data-machine-code --from lint --write
ℹ️ Collect coverage: homeboy test data-machine-code --coverage
ℹ️ Analyze failures: homeboy test data-machine-code --analyze
ℹ️ Pass args to test runner: homeboy test -- [args]
ℹ️ Full options: homeboy docs commands/test
Deep dive: homeboy test data-machine-code --changed-since 37c06d7

Audit

✅ audit — passed

• intra-method-duplication — 12 finding(s)
• dead_code — 11 finding(s)
• test_coverage — 4 finding(s)
• repeated_literal_shape — 3 finding(s)
• structural — 3 finding(s)
• dead_guard — 1 finding(s)
• duplication — 1 finding(s)
• requested_detectors — 1 finding(s)
• Total: 36 finding(s)

Deep dive: homeboy audit data-machine-code --changed-since 37c06d7

Tooling versions

• Homeboy CLI: homeboy 0.182.0+09cdec1
• Extension: wordpress from https://github.com/Extra-Chill/homeboy-extensions
• Extension revision: 24ff43e
• Action: unknown@unknown