refactor(confidence-engine): compact current-handoff to operational snapshot; archive v0.61 experiment history to ch19

- Reduce docs/current-handoff.md from 2003 → 185 lines (90% reduction)
- Move all initial-decomposition v0.61 experiment narrative to
  docs/archive/experiments/vol-1-chapters/ch19/initial-decomposition-v0.61.md
- Update design-evolution/README.md with ch19 Era 8 entry
- Add CURRENT MVP DIRECTION section (frozen; OpenAI investigation is next question)
- Fix stale branch reference in current-project-state.md
- Update Return-to-Work Summary to reflect v0.61 completion
- Update Verification Marker for v0.60/v0.61 status

docs/current-project-state.md

@@ -47,7 +47,7 @@ These are what currently affect the working engine:
 - **Question formulation** — remains an available capability (graph-backed question generation for selected nodes);
 - Scenario API (analyseScenario / updateCase);
 - Investigation turn cycle orchestration;
-- **Reasoning-fidelity v0.8 (completed):** user-supported meaning cannot silently outrun the raw answer at the mutation boundary; evidence-resolvable uncertainty and user-owned ambiguity are routed differently at question formulation. A–F regression boundaries closed for this pass. See `docs/current-handoff.md` for closeout details.
+- **Reasoning-fidelity v0.8 (completed, frozen for current MVP):** user-supported meaning cannot silently outrun the raw answer at the mutation boundary; evidence-resolvable uncertainty and user-owned ambiguity are routed differently at question formulation. A–F regression boundaries closed for this pass. See `docs/current-handoff.md` for closeout details.
 
 > **NOTE on investigation ownership:** The user currently owns which unresolved
 > investigation/question to pursue. Selector-led compulsory next-question
@@ -55,7 +55,7 @@ These are what currently affect the working engine:
 > is also paused. Question formulation remains available as a capability but its
 > output is not automatically enforced as the user's required next step.
 
-### Route architecture (v0.55)
+### Route architecture (UX/product lineage v0.51–v0.60)
 
 Three distinct routes, each with clear ownership:
 
@@ -125,7 +125,7 @@ Multi-investigation identity is durable (`uuidv4`). Legacy singleton compatibili
 
 ## 6. Work Currently Paused
 
-- Engine experiments advanced through Experiment 43 (Clarify readiness diagnostic confirming zero Clarify eligibility across all real fixtures; orienting-based rule identified as dead code; too_broad trigger validly narrow but untested in fixtures).
+- Engine experiments advanced through Experiment 43. Initial decomposition hardening (v0.61) completed and frozen for current MVP stage — see `docs/current-handoff.md` §CURRENT MVP DIRECTION.
 - UI experiments are paused;
 - Knowledge-management experiments are complete (confirmed by Experiment 38 cold-start validation);
 - Nothing historical has been deleted or archived yet.
@@ -150,16 +150,19 @@ Historical documents are retained under `docs/archive/` and should be opened onl
 
 ## 8. Return-to-Work Summary
 
-Engine experiments advanced through Experiment 43, which diagnosed Clarify's absence across all real fixtures (zero eligibility in 10 turns). The orienting-based Clarify rule is dead code — the assessor never produces phase=orienting. The too_broad trigger is validly narrow but untested by any fixture. Summarise and Pause remain operational from Exp 42. Behaviour Selection remains passive and isolated.
+Engine experiments advanced through Experiment 43 (Clarify readiness). UX/product development reached v0.60 (multi-investigation structurally complete) + v0.61 (initial decomposition hardening, frozen for MVP). Reasoning-fidelity v0.8 closed.
 
-UX/product development reached v0.55: Portfolio / Investigation / Report route separation, persisted report lifecycle (first visit = one synthesis; subsequent visits = zero), confirmation-gated restart, focused-presentation ownership per question, empty Done + Re-open semantics, zero-Open-Questions milestone. All verified via targeted Vitest and live Playwright.
+Key current state:
+- Multi-investigation architecture structurally complete (v0.60): durable IDs, listInvestigations, restart container-preserve, report freshness
+- Initial decomposition frozen (v0.61): semantically stable enough for MVP; exact topology not invariant; see CURRENT MVP DIRECTION in handoff
+- Focused deconstruction plumbing fixed and verified (48/48 tests)
+- Passive classifiers operational but isolated
 
 First document to read: **`docs/current-handoff.md`** (methodology continuity + current state), then `docs/current-project-state.md`, then `docs/project-knowledge-inventory.md`. Consult `.claude/architecture-guardrails.md` before any code changes. The full experiment history remains available in `docs/design-evolution/README.md` but is no longer default reading — load only when a specific question requires it.
 
 ## Verification Marker
 
-Implementation status last checked against source: Experiment 43.
-The current-state document was verified as accurate by focused code inspection of API routes, orchestrator imports/calls, and cross-module traces for all passive classifiers. No corrections were required.
+Implementation status last checked against source: Experiment 43 + v0.61 apparatus (tsx helper, reconstruction-only seam, focused-deconstruction schema fix). Multi-investigation architecture verified at v0.60g2+ and structurally complete. The current-state document was verified as accurate by focused code inspection of API routes, orchestrator imports/calls, and cross-module traces for all passive classifiers. No corrections were required.
 
 ## 10. Post-v0.8 Methodology Learning