perf(analytics): fast-path gates per-type only

`isFullyCovered(coverage) && specificTypes` poisoned every fast-
path with a single unrelated uncovered measurement type. v1.4.38.5
verified the discovery query was finding nothing; the slow cold-
mount was the AND-stack collapsing the gate.

- correlations-fast-path: gates on SYS + PULSE + WEIGHT only.
- bp-in-target-fast-path: gates on SYS + DIA only.
- health-score-fast-path: gates on WEIGHT only.

Coverage-probe semantics unchanged; helpers now consult the per-
type entries directly. Power-user cold-mount on /api/analytics
estimated 30-75 s → ~3-5 s.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "healthlog",
-  "version": "1.4.38.7",
+  "version": "1.4.38.8",
   "description": "Self-hosted personal-health-tracking PWA with Withings integration, AI insights, and doctor-report PDF export.",
   "license": "AGPL-3.0-only",
   "homepage": "https://healthlog.dev",