Fix MCP diagnostic authority and article checkpoint recovery (JVNAUTOSCI-2728)

[witbrock]

Merge decision: ready — authorised MCP diagnostic reads work, unavailable checkpoints cannot execute, and the existing article has been recovered with a durable successful receipt and canonical read-back.

User outcome

A coding agent can retrieve authorised local turn/workflow diagnostics through MCP, and a runtime checkout change no longer turns a recoverable article checkpoint into a falsely successful empty summary. JVNAUTOSCI-2728.

Material changes

• Preserve local operator provenance for an explicit set of diagnostic reads, while retaining signed-reference checks, existing actor scope and mutation boundaries. Reuse bounded telemetry paging for responses that exceed the stdio limit.
• Resolve the default pending blob directory through the main Git checkout so linked runtime worktrees share it. Reject unavailable complete inputs/checkpoints during execution while retaining degraded diagnostic reads.
• Update the represented article workflow to use its actual author records, carry source URL/output-key guidance, and reach successful completion only after positive summary verification.
• Record the original incident chronology, separating early partial reporting from the later restart and checkpoint failure.

Evidence

• 101 targeted authority, delegation, paging and blob tests passed.
• Six targeted represented-workflow tests passed, including false/missing verification, normal article representation, article reuse and seed migration.
• Fresh real stdio calls retrieved bounded pages for request 804d2fe7-4148-4859-9c9b-f94f7829a65e and workflow 4881438b-3281-4b0f-aeb4-58a1ebb874f5; configured-account Jira read succeeded.
• Live supervised recovery 7c371677-5684-4553-a6ae-e45c126669e2 completed six steps with workflow_completed_outputs.v1 and verification_passed=true. It reused article #V#external_identity_bibliographic_110c3e4b9ddc8590 and its existing author link, added the omitted source URL, and read all three back canonically.
• Activated and read back the selected article workflow (seed 39); unrelated workflows were not republished. Copied runtime-local pending blobs to the shared directory with byte verification, no overwrites and all originals retained.

Ship boundary

Minimum ship evidence is authorised exact-record retrieval, unchanged negative authority boundaries, recoverable checkpoint storage, honest verification finality, and canonical recovery of the existing article without duplicate concepts. Widened authority, lost state, duplicate representation or false success block merge. The original terminal instance remains an audit record; recovery uses the same article in a linked run. Broad latency tuning and unrelated workflow/tool repairs are excluded. A broader workflow-tools test run was interrupted during an external SSL wait and is not claimed as passed.