refactor(trace): enforce run-only diagnosis model

openspec/specs/session-run-trace-isolation/spec.md

@@ -53,19 +53,19 @@ The system SHALL write and read `agent_step` and `tool_invocation` rows using `r
 - **THEN** its step and tool counts SHALL be calculated from rows matching that `run_id`
 - **AND** rows from other runs in the same `sessionId` SHALL NOT be counted
 
-### Requirement: Trace API SHALL support latest-run and exact-run queries
-The system SHALL allow callers to query a diagnosis trace by `sessionId` alone for compatibility or by `sessionId + runId` for exact run replay.
+### Requirement: Trace API SHALL require an exact run
+The system SHALL require `sessionId + runId` for every diagnosis trace query and SHALL NOT infer a latest or historical run.
 
-#### Scenario: Trace without runId resolves latest run
+#### Scenario: Trace without runId is rejected
 - **WHEN** a caller requests `GET /api/diagnosis/{sessionId}/trace` without `runId`
-- **THEN** the system SHALL resolve the latest run for that session by `diagnosis_run.created_at DESC, id DESC`
-- **AND** the response SHALL include the resolved `runId`
+- **THEN** request validation SHALL reject the request
+- **AND** the service SHALL NOT infer a run from current or historical data
 
 #### Scenario: Trace with runId returns exact run
 - **WHEN** a caller requests `GET /api/diagnosis/{sessionId}/trace?runId=run-xxx`
 - **THEN** the system SHALL validate that `runId` belongs to the path `sessionId`
-- **AND** it SHALL return only the session summary, run summary, agent steps, tool invocations, self-evaluation, answer, and feedback for that run
-- **AND** the session summary SHALL come from `chat_session` metadata when available, while the run summary SHALL come from `diagnosis_run`
+- **AND** it SHALL return only chat-session metadata, run summary, agent steps, tool invocations, self-evaluation, answer, and feedback for that run
+- **AND** it SHALL NOT expose a compatibility `session` projection
 
 #### Scenario: Trace rejects run from another session
 - **WHEN** a caller requests a `runId` that belongs to a different `sessionId`
@@ -96,22 +96,11 @@ The system SHALL bind new feedback to a diagnosis run rather than an ambiguous m
 - **THEN** the system SHALL validate that the run belongs to the session
 - **AND** it SHALL update feedback on that run
 - **AND** the response SHALL include the actual bound `runId`
-- **AND** the response SHALL include `fallbackToLatestRun=false`
 
-#### Scenario: Feedback without runId falls back observably
-- **WHEN** a legacy feedback request includes `sessionId` but omits `runId`
-- **AND** at least one `diagnosis_run` exists for that session
-- **THEN** the system SHALL bind feedback to the latest run for that session
-- **AND** the response SHALL include `fallbackToLatestRun=true`
-- **AND** the response SHALL include the actual bound `runId`
-
-#### Scenario: Historical feedback without run-backed data remains compatible
-- **WHEN** a legacy feedback request includes `sessionId` but omits `runId`
-- **AND** no `diagnosis_run` exists for that session
-- **AND** a historical `diagnosis_session` row exists for that session
-- **THEN** the system MAY bind feedback to the historical session row for migration compatibility
-- **AND** the response SHALL NOT claim latest-run fallback
-- **AND** the response MAY omit `runId`
+#### Scenario: Feedback without runId is rejected
+- **WHEN** a feedback request includes `sessionId` but omits `runId`
+- **THEN** the system SHALL reject the request
+- **AND** it SHALL NOT bind feedback to any run
 
 #### Scenario: Feedback rejects run from another session
 - **WHEN** a feedback request includes a `runId` that belongs to a different `sessionId`
@@ -140,18 +129,13 @@ The system SHALL create and expose a diagnosis run for every valid `/api/ai_ops`
 - **AND** the metadata payload SHALL expose the created `runId`
 - **AND** report content SHALL continue to use the existing content message shape
 
-### Requirement: Migration SHALL preserve historical trace access
-The system SHALL migrate historical diagnosis data into compatibility runs without deleting the old `diagnosis_session` table.
+### Requirement: Runtime SHALL use only run-based diagnosis storage
+The system SHALL use `chat_session` and `diagnosis_run` as the only runtime diagnosis model and SHALL NOT read or write `diagnosis_session`.
 
-#### Scenario: Historical session gets compatibility run
-- **WHEN** migration runs on an existing `diagnosis_session` row
-- **THEN** the system SHALL create a compatible `diagnosis_run` row for that session
-- **AND** old `agent_step` and `tool_invocation` rows for that session SHALL be backfilled to that `run_id` when possible
-
-#### Scenario: Old table is retained
-- **WHEN** the migration completes
-- **THEN** the `diagnosis_session` table SHALL remain available for historical comparison and rollback
-- **AND** new execution writes SHALL target `chat_session` and `diagnosis_run`
+#### Scenario: Runtime components are inspected
+- **WHEN** Trace, Feedback, Evaluation, AIOps persistence, Gatekeeper, and case creation execute
+- **THEN** they SHALL resolve data by `runId`
+- **AND** no executable entity, repository, service fallback, or test SHALL depend on `diagnosis_session`
 
 ### Requirement: Demo and Trace UI SHALL support runId
 The demo tooling and Trace UI SHALL support minimal run-aware workflows.
@@ -214,14 +198,14 @@ The Trace API SHALL parse the current DiagnosisRun orchestration JSON and expose
 
 - **WHEN** a caller queries a successful new StateGraph Chat run
 - **THEN** `run.orchestrationTrace` SHALL be a non-empty parsed JSON object
-- **AND** the response top level and compatibility `session` projection SHALL NOT duplicate the field
+- **AND** the response SHALL NOT contain a compatibility `session` projection
 - **AND** no raw orchestration trace field SHALL be added
 
-#### Scenario: Historical or non-StateGraph run is queried
+#### Scenario: Non-StateGraph run is queried
 
 - **WHEN** the selected DiagnosisRun has null orchestration trace
 - **THEN** `run.orchestrationTrace` MAY be null
-- **AND** the service SHALL NOT synthesize historical events or read another run's trace
+- **AND** the service SHALL NOT synthesize events or read another run's trace
 
 ### Requirement: Orchestration trace migration SHALL be additive and nullable