Fix orchestration follow-ups and selected model routing

[Paul Lizer (paullizer)]

Summary

• Fix the second-question failure caused by rejecting otherwise valid resolver JSON with an unused clarification: null. Retain strict history/ID validation and bounded correction of malformed responses.
• Honor the manually selected model or admin default across orchestration instead of silently choosing the legacy GPT-4o configuration. Pin the authorized answer selection through approval, clarification, replanning and conversational plan editing; keep dedicated planner overrides independent.
• Persist and stream actual answer-model metadata, fail explicitly on unusable answers, and normalize Anthropic completion reasons without accepting truncated or refused output.
• Integrate the current V2 inline-answer, approval-persistence and conversational plan-editing changes. Preserve atomic revision/execution claims, close prepared model clients on claim failures, and advance the application to 0.261.103.

Target: paullizer-react-v2-ui, the active integration branch this work depends on. The diff is limited to 23 fix-related files; this is not a promotion of the V2 branch into Development. Merge conflicts with the latest plan editor are resolved in da958455.

Linked issue

N/A.

Release Notes & Latest Features

• New Feature
• Bug Fix
• UI Enhancement
• Breaking Change
• Internal only

Is this visible to end users?

• Yes
• No

Is this admin-facing (Admin Settings, governance, deployment, config)?

• Yes
• No

Should this become a Latest Feature card?

• Yes
• No
• Already added

Screenshot needed for the card?

• Yes
• No
• Attached

Version bump

• application/single_app/config.py VERSION third segment bumped to 0.261.103
• deployers/version.txt not needed because deployers/ was not changed

Testing / validation

• python -m pytest -q --tb=short --disable-warnings over 18 targeted orchestration, revision, model endpoint, prompt-fill, elicitation and approval-persistence suites: 394 tests and 291 subtests passed after integration with the current V2 base. The clarification fixture now reloads the revision modules with its per-test store instead of retaining another suite's Cosmos boundary.
• The conversation-context, plan-editor and browser-to-Flask plan-editor suites passed 39 tests and 3 subtests, including selected Terra model continuity through edits, questions, restoration and execution, plus the visible answering-model label.
• The existing V2 production build passed with output directed into UI test artifacts, not tracked application assets.
• Route policy inventory/access/coverage scripts, documentation surface/quality scripts, and adapter/invoke-prompt contracts passed. The regenerated documentation inventory is unchanged.
• Before this merge-conflict resolution, a two-turn synthetic replay used the real configured Terra SDK endpoint with in-memory conversation/run containers. All three completions used Terra; no production conversations or settings were written. No deployment was performed.
• Four additional adjacent tabular/export-summary test failures were reproduced against unchanged baseline 6a34c8a6: an exact historical version assertion and three extracted-helper tests missing build_model_endpoint_identity_headers. Those unrelated tests and the export route are unchanged. Details are in the model-selection fix documentation.

Documentation

• Release notes updated, or not needed — release-note edits remain deferred; this PR does not add its own release-note entry.
• Feature and admin documentation updated
• Fix documentation updated, including ORCHESTRATION_MODEL_SELECTION_FIX.md and ORCHESTRATION_CONVERSATION_CONTEXT_FIX.md

No new configuration key, dependency, schema migration or deployment configuration is required.

Security checklist

• Existing Flask route Swagger/authentication decorators preserved, including editor endpoints; the fix adds no routes
• No raw settings sent to non-admin frontends; model metadata excludes credentials and endpoint addresses
• Browser JavaScript remains local-only; no CDN assets added
• No secrets, keys, connection strings or local-only artifacts included