docs: add workspace reimplementation proposal slices

[TabishB]

Summary

Adds a lightweight OpenSpec planning layer for reimplementing workspace support without nesting changes under a parent directory.

This PR adds one roadmap proposal plus six flat sibling proposal changes:

• workspace-reimplementation-roadmap
• workspace-foundation
• workspace-create-and-register-repos
• workspace-open-agent-context
• workspace-change-planning
• workspace-apply-repo-slice
• workspace-verify-and-archive

It also adds the handoff/reference material a fresh agent needs before implementation:

• WORKSPACE_REIMPLEMENTATION_START_HERE.md: grep-friendly root entrypoint with search terms, reading order, implementation order, and before-editing checklist
• WORKSPACE_REIMPLEMENTATION_DIRECTION.md: full direction document copied from workspace-poc at 79a45ac043f414e63d13e08b9da83b135cb20a39
• openspec/changes/workspace-reimplementation-roadmap/README.md: implementation order, dependency notes, branch/session handoff guidance
• openspec/changes/workspace-reimplementation-roadmap/POC_REFERENCE_GUIDE.md: how a new agent should inspect the POC, which files to read by slice, and what findings to bring back before editing

The roadmap records workspace-poc @ 79a45ac043f414e63d13e08b9da83b135cb20a39 as reference material only. Dependencies are documented in proposal prose for now because current OpenSpec change discovery expects flat immediate directories under openspec/changes/, and formal change stacking metadata is not implemented yet.

Verification

• openspec list --json
• git hash-object WORKSPACE_REIMPLEMENTATION_DIRECTION.md
• git rev-parse 79a45ac043f414e63d13e08b9da83b135cb20a39:WORKSPACE_REIMPLEMENTATION_DIRECTION.md
• rg -n "workspace reimplementation|workspace poc|fresh agent|start here|workspace reference guide|workspace roadmap" WORKSPACE_REIMPLEMENTATION_START_HERE.md WORKSPACE_REIMPLEMENTATION_DIRECTION.md openspec/changes/workspace-reimplementation-roadmap

Confirmed all seven proposal-only changes are discovered as flat active changes with no-tasks status. Confirmed the copied WORKSPACE_REIMPLEMENTATION_DIRECTION.md matches the pinned POC blob exactly. Confirmed obvious grep terms surface the root start-here guide and roadmap materials.

Notes

• No runtime code changes.
• No nested change directories.
• gh auth status reports the local GitHub CLI token is invalid, so this PR was opened and updated with the GitHub connector.

Summary by CodeRabbit

• Documentation
  • Added comprehensive planning documentation for multi-repository workspace support, outlining the intended user workflow for creating workspaces, registering repositories, planning cross-repo changes, applying implementations to individual repositories, and verifying/archiving workspace completion.
  • Established the implementation roadmap and reference materials for workspace reimplementation.

[coderabbitai]

Caution

Review failed

Pull request was closed or merged during review

📝 Walkthrough

Walkthrough

Introduces comprehensive documentation for reimplementing OpenSpec multi-repo workspace support, including a north-star design direction, implementation roadmap with six sequential phases, POC reference guide, and detailed specification proposals for workspace creation, registration, agent context, change planning, repo-slice apply, and verify/archive workflows.

Changes

Cohort / File(s)	Summary
Core Direction & Roadmap WORKSPACE_REIMPLEMENTATION_DIRECTION.md, WORKSPACE_REIMPLEMENTATION_START_HERE.md, openspec/changes/workspace-reimplementation-roadmap/*	Establishes the north-star user workflow for multi-repo workspace support, enumerates six implementation slices in sequence order, provides POC reference guidance with pinned commit, and defines operational handoff prompts for implementation sessions.
Workspace Foundation & Setup openspec/changes/workspace-foundation/proposal.md, openspec/changes/workspace-create-and-register-repos/proposal.md	Specifies workspace root detection, metadata directory conventions, repo registry with stable aliases, and initial user workflow to create workspace and register repositories without requiring prior change creation.
Workspace Coordination & Agent Integration openspec/changes/workspace-open-agent-context/proposal.md, openspec/changes/workspace-change-planning/proposal.md	Defines agent context injection for opening workspaces, launch-context separation, workspace-level change planning with repo target resolution, and exploration semantics prior to implementation commitment.
Workspace Implementation & Lifecycle openspec/changes/workspace-apply-repo-slice/proposal.md, openspec/changes/workspace-verify-and-archive/proposal.md	Specifies repo-slice apply workflow that injects workspace plan context without materializing planning artifacts, and verify/archive semantics with per-repo progress reporting and final workspace completion marking.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Possibly related PRs

• docs: clarify initiative-first workspace model #969: Adopts the same initiative-first planning separation (coordination workspace vs. repo-local execution) in workspace-change-planning and related proposals.
• feat(skills): add /opsx:verify change proposal #497: The workspace verify-and-archive proposal explicitly updates the opsx-verify-skill capability that is introduced in this PR.
• chore: archive completed changes and clean up stale ones #455: Both PRs modify cli-artifact-workflow apply/instructions/status semantics for workspace-aware behavior.

Suggested reviewers

• alfred-openspec

Poem

🐰 A workspace grand, from north to south we plot,
Six slices stacked, in careful ordered knot,
Registry roots and agent-guided hands,
We bound the realm with clear and durable strands! ✨

🚥 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 accurately summarizes the main change: adding workspace reimplementation proposal slices as documentation, which is precisely what the PR does.
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 unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/workspace-reimplementation-proposals

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[alfred-openspec]

Looks clean. The roadmap, slice breakdown, and fresh-agent handoff docs all line up, and I didn’t spot any structural issues in the proposal-only changes.