feat(agent): telemetry + CI-gate quick wins from the "AI systems that ship" audit (#677)

* feat(agent): telemetry completeness + durability, CI gates, commit_method provenance

Quick wins from the "Building AI systems that ship" audit:

- mcp.tool_called gains errorMessage (message_sv, truncated 500 chars) on
  all failure exits; new mcp.skill_loaded event on every gnubok_load_skill
  (all tiers) so atom usage is finally measurable
- event_log: (event_type, created_at) index; cleanup cron keeps
  mcp.*/agent.* telemetry 180 days (delivery events stay 30)
- CI: lint ratchet (npm run check:lint — 60 legacy errors baselined,
  fails only on NEW errors) and a pg-real coverage gate (migrations
  touching trigger/RPC/RLS/DEFERRABLE require a *.pg.test.ts change;
  escape hatch: -- pg-test: covered-by/skip)
- journal_entries.commit_method CHECK widened with 'api_key'/'agent';
  the MCP approve path records 'api_key' truthfully instead of
  'user_accept' (agent_first_vision §8 P0-1). 'agent' is reserved — ALL
  MCP traffic (incl. claude.ai OAuth, whose access_token is a minted
  API key) authenticates as api_key today

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* feat(import): derive opening balances from prior-year #UB when SIE lacks #IB (#675)

SIE files exported without #IB 0 rows (only #UB -1) previously imported
with zero opening balances. getEffectiveOpeningBalances() now derives IB
from prior-year UB for balance-sheet accounts when explicit #IB is
absent, surfaces the derivation as an info issue in the import preview,
and excludes share-capital vouchers from opening-balance detection.
Detection regexes are shared between parser and importer so the two
checks cannot drift. 507 lib/import tests pass.

(Authored in a parallel session in this checkout; included per request.)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(review): address PR #677 bot findings — RoPA entry, execFileSync, gate scope note

Triage of the compliance-swarm + Greptile findings:

Applied:
- .compliance/ropa.yaml: new mcp.telemetry processing activity declaring
  the 180-day mcp.*/agent.* retention, lawful basis, data categories, and
  the no-args/no-results minimisation (ISO A.8.10, GDPR Art.5(1)(c) —
  the retention split is now formally documented, referenced from the cron)
- check-pg-test-coverage.mjs: execFileSync with argv array — no shell, so
  a hostile base-ref can't inject (ASVS V13.2.1); verified an injection
  attempt exits 2 without executing
- check-pg-test-coverage.mjs: documented the PR-level (not per-migration)
  scope of the gate so reviewers know to check coverage per migration when
  a PR carries several risky migrations (Greptile P2)

Acknowledged, no change:
- errorMessage PII risk: messages are domain-mapped strings; event_log
  already persists far richer delivery payloads under the same RLS; now
  declared in ropa.yaml
- cron error envelope: errorResponse maps to the canonical safe envelope
  and the endpoint is CRON_SECRET-gated
- two-pass delete "partial state": TTL deletes are idempotent — the next
  daily run sweeps whatever a failed pass left behind
- skill_loaded actorLabel/sessionId: mirrors the pre-existing
  mcp.tool_called payload; sessionId is the join key the analytics exist for

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

supabase/migrations/20260618120000_event_log_type_index.sql

@@ -0,0 +1,12 @@
+-- Telemetry analytics index for event_log.
+--
+-- mcp.tool_called / mcp.skill_loaded / agent.feedback analytics filter by
+-- event_type + time window (error rate per tool, feedback themes, skill-load
+-- correlation). The existing indexes cover only (user_id, sequence) for
+-- delivery polling and (created_at) for TTL cleanup — every per-type query
+-- was a full scan. Also serves the differentiated-retention deletes in
+-- /api/events/cleanup/cron (telemetry kept 180 days, delivery events 30).
+CREATE INDEX IF NOT EXISTS idx_event_log_type_created
+  ON public.event_log (event_type, created_at);
+
+NOTIFY pgrst, 'reload schema';

supabase/migrations/20260618120001_commit_method_agent_provenance.sql

@@ -0,0 +1,31 @@
+-- Agent attribution into the immutable layer (agent_first_vision.md §8 P0-1).
+--
+-- journal_entries.commit_method could not record that a commit was approved
+-- through an agent credential: the MCP approve path hardcoded 'user_accept',
+-- so an auditor reading the immutable GL could not distinguish agent-relayed
+-- acknowledgments from first-party human sessions. BFNAR 2013:2 kap 8
+-- (behandlingshistorik) requires automated processing to be identifiable.
+--
+--   'api_key' — approval relayed by an agent authenticating with a gnubok_sk_
+--               API key. This covers ALL MCP traffic today: the gnubok-mcp
+--               bridge AND the claude.ai OAuth connector, whose access_token
+--               is itself a minted API key (app/api/mcp-oauth/token/route.ts)
+--               and is indistinguishable from a bridge key at the server.
+--   'agent'   — reserved for first-party agent surfaces (e.g. in-app agent
+--               chat) once they commit through the approval layer with a
+--               distinguishable actor type. Not written by any path yet.
+--
+-- Web-UI approvals keep 'user_accept' / 'bulk_accept'. Every path remains
+-- human-approval-gated; agent auto-commit stays removed (20260505190027).
+
+ALTER TABLE public.journal_entries
+  DROP CONSTRAINT IF EXISTS journal_entries_commit_method_check;
+
+ALTER TABLE public.journal_entries
+  ADD CONSTRAINT journal_entries_commit_method_check
+  CHECK (commit_method IS NULL OR commit_method IN (
+    'user_accept', 'bulk_accept', 'timing_ceiling', 'migration', 'legacy',
+    'agent', 'api_key'
+  ));
+
+NOTIFY pgrst, 'reload schema';