Adopt lossless repository identity across runtime consumers

[TheGreenCedar]

Parent: #913

Outcome

Adopt the versioned lossless repository identity from #974 across every runtime consumer so broker, repair, sidecar, and plugin routing cannot collide case-sensitive repositories or non-default ports.

Acceptance criteria

• Readiness-broker snapshots, locks, operation identities, and cleanup paths use the schema-v3 repository/workspace identity.
• Ready/repair ownership uses filesystem-aware path equality and cannot match a distinct case-sensitive repository.
• Plugin JavaScript request routing preserves non-default remote ports and case-sensitive path components; it remains request-scoped with no global active project.
• Existing schema-v1/v2 state is reused only through a provably safe legacy alias; ambiguous/colliding state is isolated and rebuilt.
• Portable worktree reuse retains one repository id with distinct workspace ids and explicit artifact-scope eligibility.
• Cross-process A/B/A tests cover case-distinct Unix paths, Windows aliases, non-default ports, safe migration, and collision rejection.
• Update identity architecture/operator docs and changelog.

Non-goals

• Do not invent another identity type; consume the contract already merged by Version the lossless repository identity contract #974.
• Do not preserve unsafe legacy reuse merely to avoid a rebuild.

Refs #899

Workstreams

• Migrate broker and repair ownership to project identity v3 #1033 — migrate broker and repair ownership to project identity v3
• Migrate sidecar state and artifact scopes to project identity v3 #1034 — migrate sidecar state and artifact scopes to project identity v3
• Make plugin project routing filesystem-aware and request-scoped #1035 — make plugin project routing filesystem-aware and request-scoped