Stabilize runtime hard-cut verification

[TraderSamwise]

Summary

• make root Vitest verification deterministic for the runtime hard-cut harness
• update stale multi-client and authority docs so instances/worktree-graveyard remain legacy-only
• record the final audit behavior in the runtime-core roadmap

Verification

• yarn verify
• yarn build
• rg audit for instances/worktree-graveyard active authority paths

Summary by CodeRabbit

• Documentation

  • Updated Multi-Client Runtime documentation to reflect current system architecture and topology-based behavior
  • Clarified authority and ownership semantics across runtime system reference documents
  • Updated roadmap with specific guidance on current development state and test harness requirements

• Chores

  • Configured test suite to run serially for improved stability

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR refocuses authority ownership for runtime services, worktrees, and multi-client presence from legacy file/registry sources to topology-backed records. All changes are documentation and configuration; the single code change disables parallel test execution to ensure deterministic behavior with harness-level mocks.

Changes

Authority Model and Testing

Layer / File(s)	Summary
Authority Model Shift in Domain Matrix and RFC docs/runtime-authority-inventory.md, docs/global-control-plane-rfc.md, docs/runtime-authority-dead-paths.md, docs/runtime-core-hard-cut-roadmap.md	Domain matrix marks Services, Worktrees, and Worktree graveyard as TOPOLOGY authority instead of LEGACY. RFC guidance moves presence handling from instance registry to relay/share semantics. Dead-path checklist asserts topology-backed durability for worktree status/graveyard and forbids restoring .aimux/worktree-graveyard.json as authority. Roadmap cut-line bullets refine coverage specifics for service/worktree lifecycles and relay-owned remote semantics.
Multi-Client Runtime User Documentation README.md	README replaces "Multi-Instance" section with "Multi-Client Runtime," centering on runtime topology rather than instance heartbeat registry. Documents that .aimux/instances.json is non-authoritative and that --resume and offline visibility decisions are topology-based.
Vitest Serial Execution Configuration docs/runtime-core-hard-cut-roadmap.md, vitest.config.ts	Vitest configuration sets fileParallelism: false to enforce serial test execution. Roadmap documentation explains that the reliability harness requires serialization due to process-level mocks and shell-script fakes; parallelism is opt-in via explicit Vitest CLI override only.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• TraderSamwise/aimux#29: Updates runtime authority documentation to shift durable ownership to topology and away from legacy instances.json and graveyard semantics across the same authority and roadmap documentation files.

Poem

🐰 Topology takes the throne so high,
Legacy files wave their goodbye;
Authority flows through YAML's embrace,
Tests run serially, steady the pace. ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Stabilize runtime hard-cut verification' directly aligns with the main change: making Vitest verification deterministic by disabling file parallelism, and updating documentation to finalize the runtime hard-cut audit.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch phase/reliability-harness-final-audit

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[coderabbitai]

🧹 Nitpick comments (1)

README.md (1)

776-784: ⚡ Quick win

Align older README terminology with this new “Multi-Client Runtime” language.

This section is clear, but the earlier Features list still uses “Multi-instance,” which now reads as legacy phrasing and can confuse readers.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@README.md` around lines 776 - 784, Update README terminology to replace
legacy "Multi-instance" phrasing with the new "Multi-Client Runtime" language
and clarify affected references; search the README Features list and any
headings/descriptions that mention "Multi-instance" and change them to
"Multi-Client Runtime", update examples or flags that imply the old name (keep
`.aimux/instances.json` and `--resume` notes intact as legacy/behavioral
references), and ensure wording aligns with the new section text (e.g., mirror
phrases like "session lifecycle, ownership, graveyard state" from the
Multi-Client Runtime block to the Features summary).

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@README.md`:
- Around line 776-784: Update README terminology to replace legacy
"Multi-instance" phrasing with the new "Multi-Client Runtime" language and
clarify affected references; search the README Features list and any
headings/descriptions that mention "Multi-instance" and change them to
"Multi-Client Runtime", update examples or flags that imply the old name (keep
`.aimux/instances.json` and `--resume` notes intact as legacy/behavioral
references), and ensure wording aligns with the new section text (e.g., mirror
phrases like "session lifecycle, ownership, graveyard state" from the
Multi-Client Runtime block to the Features summary).

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 29c4285d-5e00-4319-b4a2-054dcf66507c

📥 Commits

Reviewing files that changed from the base of the PR and between 3b6cab3 and b5a430b.

📒 Files selected for processing (6)

• README.md
• docs/global-control-plane-rfc.md
• docs/runtime-authority-dead-paths.md
• docs/runtime-authority-inventory.md
• docs/runtime-core-hard-cut-roadmap.md
• vitest.config.ts