M8: GUI polish, n8n workflow-3 fixes, RAGcore retrieval root-cause and fix

GUI: dashboard Attention Queue presents a curated severity mix instead of pure
severity-sort (grouped Now/Today/Later headers); Today's Movements seed data
curated so a fresh reset shows a credible day (2+ departures, 2+ returns), with
a new seed-integrity test; About Demo restructured into a compact grid with
progressive disclosure for technical sections; Duplicate Merge shows match/conflict
counts, hides matching fields by default, and previews the final merged record
before confirmation.

Repo hygiene: removed a stray empty `backend;C` directory and an untracked 31MB
zip export; `.gitignore` now excludes future archive exports.

n8n: fixed invalid JSON (a missing `},` between two node objects) in the committed
`fleet-ops-vehicle-return.json` -- the file could not be parsed. Live-validated
workflow 3 (RAGcore Procedure Sync): found and fixed a real defect (three body
parameters had a stray trailing `}}`) and a missing Error Workflow wiring, both
via the safe `n8n import:workflow` CLI path; exported the corrected, still-
inactive workflow as the new source of truth and updated MANIFEST.md/check_drift.py.
Publishing it (starts real daily unattended runs) remains a separate decision.

RAGcore: root-caused and fixed (live, approved) the "zero retrieval candidates"
bug -- a filesystem permission bug (`embedding_profiles.json` unreadable by the
app's own runtime user) that broke every retrieval call before it reached Qdrant.
Every other suspect (grants, scope resolution, Qdrant filters, embeddings) was
verified healthy first. Found a second, deeper gap: the reranker adapter calls
an Ollama HTTP route that does not exist on the deployed Ollama version, so
`/v1/answers` still returns `not_answerable`. `KNOWLEDGE_PROVIDER` stays `demo`
until that is resolved on the RAGcore side. Evidence-based MCP Hub integration
status (real tool-call audit history, not just a boolean flag) replaces the old
`configured`/`not_configured` guess. Full findings in
`docs/final-integrations/current-state-audit.md`.

Backend: 172 tests passing, ruff clean, mypy clean (50 files). Frontend: tsc
clean, production build clean.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

seed/bookings.csv

@@ -1,5 +1,5 @@
 public_ref,customer_ref,vehicle_ref,starts_at,ends_at,status,start_odometer_km,end_odometer_km,requirements_complete
-BK-H-0001,CUS-0012,MO-008,2026-07-26T08:00:00Z,2026-07-29T08:00:00Z,returned,20932,21133,true
+BK-H-0001,CUS-0012,MO-008,2026-07-29T08:00:00Z,2026-08-01T08:00:00Z,returned,20932,21133,true
 BK-H-0002,CUS-0023,MO-015,2026-07-24T07:00:00Z,2026-07-28T07:00:00Z,returned,26659,26861,true
 BK-H-0003,CUS-0034,MO-022,2026-07-22T06:00:00Z,2026-07-27T06:00:00Z,returned,31407,31610,true
 BK-H-0004,CUS-0045,MO-029,2026-07-20T05:00:00Z,2026-07-26T05:00:00Z,returned,36708,36912,true
@@ -220,8 +220,8 @@ BK-H-0218,CUS-0059,MO-027,2025-12-14T07:00:00Z,2025-12-24T07:00:00Z,returned,352
 BK-H-0219,CUS-0070,MO-034,2025-12-12T06:00:00Z,2025-12-23T06:00:00Z,returned,39838,40257,true
 BK-H-0220,CUS-0081,MO-041,2025-12-20T05:00:00Z,2025-12-22T05:00:00Z,returned,45223,45643,true
 BK-DEMO-RETURN,CUS-0042,MO-024,2026-07-28T09:00:00Z,2026-08-01T09:00:00Z,active,53610,,true
-BK-F-001,CUS-0014,MO-010,2026-08-03T10:00:00Z,2026-08-07T10:00:00Z,reserved,,,true
-BK-F-002,CUS-0027,MO-019,2026-08-04T11:00:00Z,2026-08-09T11:00:00Z,reserved,,,true
+BK-F-001,CUS-0014,MO-010,2026-08-01T10:00:00Z,2026-08-05T10:00:00Z,reserved,,,true
+BK-F-002,CUS-0027,MO-019,2026-08-01T11:00:00Z,2026-08-06T11:00:00Z,reserved,,,true
 BK-F-003,CUS-0040,MO-028,2026-08-05T12:00:00Z,2026-08-11T12:00:00Z,reserved,,,false
 BK-F-004,CUS-0053,MO-037,2026-08-06T13:00:00Z,2026-08-13T13:00:00Z,reserved,,,true
 BK-F-005,CUS-0066,MO-046,2026-08-07T09:00:00Z,2026-08-15T09:00:00Z,reserved,,,true