feat(orchestration): plan grounding, positive-pattern mining, stage-prompt audition rig

Vikunja #167/#168/#169.

#167 PlanGrounder (infrastructure/workflow): build-prereq + touches-scope
existence grounding, emits PlanGroundingEvaluatedEvent. Deterministic fold
over recorded workspace/plan events (invariants #8/#9).

#168 positive-pattern mining (SessionOrchestratorPlanPatterns): mine
SuccessfulPlanShape from cross-session log — a locked plan whose own
workflow later completed — and inject the closest-resembling plan shape as
L0/SYSTEM advisory context for the planning stage. Keyword-Jaccard
resemblance, no LLM/embedder, replays identically. Advisory only (#3).

#169 stage-prompt audit + CORREX_STAGE_GUIDANCE ON/OFF toggle in
SessionOrchestratorExecution. RunCommand gains --intent to seed a
freestyle session over REST.

Also: workspace verification events + concept-compiler wiring. ./gradlew
check green.

infrastructure/src/test/kotlin/com/correx/infrastructure/InfrastructureModuleModelTest.kt

@@ -52,7 +52,7 @@ class InfrastructureModuleModelTest {
         val descriptor = InfrastructureModule.modelConfigToDescriptor(config)
 
         assertEquals("bare-model", descriptor.modelId)
-        assertEquals(8192, descriptor.contextSize)
+        assertEquals(24_576, descriptor.contextSize)
         assertEquals(0, descriptor.capabilities.size)
     }