…oala73#168)

### Motivation
- Reduce sidecar API egress by preferring Brotli (br) for clients that
support it while keeping gzip as a fallback for broad compatibility.
- Ensure the sidecar negotiates compression consistently (set
`Content-Encoding`, append `Vary: Accept-Encoding`) and avoids sending
stale `Content-Length` when responses are compressed.
- Provide an Nginx proxy baseline that preserves client
`Accept-Encoding` and prefers Brotli at the proxy layer.

### Description
- Updated `src-tauri/sidecar/local-api-server.mjs` to negotiate response
compression via a new `maybeCompressResponseBody` routine that prefers
Brotli (`br`) and falls back to gzip for payloads > 1KB, preserves
existing `Content-Encoding` from handlers, and appends `Vary:
Accept-Encoding` when compressing.
- Added a small helper `canCompress` and promisified `brotliCompress` so
Brotli compression runs asynchronously while gzip remains synchronous
for fallback.
- Ensure `Content-Length` is removed when `Content-Encoding` is applied
so downstream callers/proxies don't see stale lengths.
- Added tests to `src-tauri/sidecar/local-api-server.test.mjs` that
verify Brotli is preferred when `Accept-Encoding` includes `br` and gzip
is used when `br` is not present, including decompression checks with
`brotliDecompressSync`/`gunzipSync`.
- Added `deploy/nginx/brotli-api-proxy.conf` as an example Nginx
configuration enabling Brotli with gzip fallback and forwarding
`Accept-Encoding` while disabling upstream decompression (`gunzip off`).
- Updated `README.md` to reflect the sidecar now advertising `br/gzip`
behavior and adjusted the expected payload reduction notes.

### Testing
- Ran the sidecar unit tests with `node --test
src-tauri/sidecar/local-api-server.test.mjs`, which executed 19 tests
and all passed (`# pass 19`, `# fail 0`).
- No other automated test suites were modified; the new tests are
self-contained under the sidecar test file and validated the compression
behavior.

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[Codex
Task](https://chatgpt.com/codex/tasks/task_e_6997871302188333bb1ecb20714d2ad3)

…riter

Resolves all 5 critical findings from the multi-agent code review of PR #2940.
End-to-end smoke test passes for all 8 regions with confidence=1.0.

P1 #166: health-seed-meta-not-in-keys-loops
  - Add regionalSnapshots to STANDALONE_KEYS in api/health.js
  - Without this, the SEED_META entry was dead wiring and the 12h staleness
    budget was unobservable. Same failure mode as the 'empty data ok keys
    bootstrap blind spot' the team has hit before.

P1 #167: oref-trigger-key-not-in-freshness-registry
  - Add relay:oref:history:v1 to FRESHNESS_REGISTRY (the canonical OREF key
    written by ais-relay, not the wrong intelligence:oref-alerts:v1 that the
    code was originally reading).
  - Update trigger-evaluator to read activeAlertCount/historyCount24h from
    the actual relay:oref:history:v1 payload shape.
  - oref_cluster trigger now fires when activeAlertCount > 10 (verified
    end-to-end against mock data).

P1 #168: zombie-freshness-registry-keys
  - Remove 4 freshness registry entries that no compute module reads:
    supply_chain:shipping_stress, energy:chokepoint-flows,
    intelligence:advisories-bootstrap, market:commodities-bootstrap.
  - These were dragging snapshot_confidence below 1.0 and wasting Redis
    pipeline reads. Add a header comment forbidding speculative entries.

P1 #169: diff-field-leaks-into-persisted-snapshot
  - Change computeSnapshot to return { snapshot, diff } separately so the
    diff is consumed locally for inferTriggerReason and never serialized
    into the persisted snapshot. The diff field was not part of the
    RegionalSnapshot type and would have broken Phase 1 proto codegen.
  - Update main() to destructure { snapshot } before persistSnapshot.

P1 #170: jsdoc-types-not-enforced-jsconfig-missing
  - Add scripts/seed-regional-snapshots.mjs and scripts/regional-snapshot/**
    to scripts/jsconfig.json's include array so tsc --checkJs validates the
    JSDoc @type annotations.
  - Add // @ts-check directive to all 14 .mjs files in the regional-snapshot
    pipeline.
  - Fix 4 type-safety bugs surfaced by enabling type-checking:
      actor-scoring: explicit ActorState[] type on local actors array; cast
        leverage_domains to ActorLeverageDomain[]; typed ActorRole return on
        inferRole.
      evidence-collector: explicit EvidenceItem[] type on local out array.
      scenario-builder: typed HORIZONS as ScenarioHorizon[] and LANE_NAMES
        as ScenarioName[].
      transmission-templates: cast tpl.affectedRegions to RegionId[] when
        building TransmissionPath objects.
  - Pre-existing seed-forecasts.mjs and _r2-storage.mjs errors (46 total)
    are not part of this PR's scope and remain untouched.

Verification
  - npx tsc --noEmit -p scripts/jsconfig.json: 0 errors in regional-snapshot files
  - npm run typecheck:all: clean
  - npm run test:data: 3946/3946 pass
  - tests/regional-snapshot.test.mjs: 50/50 pass
  - End-to-end smoke test: all 8 regions compute clean with confidence=1.0
  - Verified: oref_cluster trigger fires when activeAlertCount > 10
  - Verified: persisted snapshot has no diff field