feat(fires): FRP intensity filter, confidence switch and six-stop color ramp (HAL-676)

Color every FIRMS detection by fire radiative power on the Portolan
cold → hot ramp (blue · teal · lime · amber · orange · red at
0 · 5 · 20 · 50 · 100 · 300 MW), replacing the three warm stops that
made a 2 MW and a 40 MW fire look alike. Heat cells, glow sprites and
card accents all read the same ramp (src/data/firmsIntensity.js).

Add a minimum-FRP log slider whose track is painted with the ramp (so
it doubles as the legend), an All / Nominal+ / High confidence switch
and an "N of M shown" counter to the Active Fires row. The filter runs
once in ingestion.applyFilter(), so markers, cards, heat cells, the
context store, the top-fires query and the analyst records all see one
set. Default is 0 MW / All: many of the strongest fires are rated low.

Persist both options in the layer state (token w: minFrp `f`,
confidence `c`), including the short share codec, and give the agent's
get_active_fires tool matching min_frp_mw / confidence arguments.

Layer panel gains generic `slider` and `segmented` row descriptors
(src/ui/rowFilterControls.js). New strings in es / ru / zh-CN.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

src/data/layerState.js

@@ -298,6 +298,20 @@ function satelliteFilterOption() {
 }
 
 const OPTION_GROUPS = Object.freeze({
+  // Active Fires intensity filter (HAL-676). `minFrp` is whole megawatts on
+  // the codec side; the panel's log slider rounds to it. Both default to
+  // "show everything": many of the strongest fires are rated low confidence.
+  // The bounds and modes mirror MIN_FRP_MW_MAX / FIRMS_CONFIDENCE_MODES in
+  // firmsIntensity.js (pinned by layerState.test); spelled out here because
+  // this file runs in isolation in the token-ledger tests.
+  'local-firms': Object.freeze([
+    boundedIntegerOption('minFrp', 'f', 0, { min: 0, max: 10000 }),
+    enumOption('confidence', 'c', 'all', ['all', 'nominal', 'high'], {
+      all: 'a',
+      nominal: 'n',
+      high: 'h',
+    }),
+  ]),
   traffic: Object.freeze([
     enumOption('roadMode', 'r', null, ['tomtom', 'osm', 'hybrid'], {
       tomtom: 't',
@@ -621,7 +635,12 @@ export const LAYER_STATE_REGISTRY = Object.freeze([
     token: 'd',
     disposition: 'enabled-only',
   }),
-  Object.freeze({ id: 'local-firms', token: 'w', disposition: 'enabled-only' }),
+  Object.freeze({
+    id: 'local-firms',
+    token: 'w',
+    disposition: 'enabled+options',
+    optionOwner: 'local-firms',
+  }),
   Object.freeze({
     id: 'military',
     token: 'm',