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/i18n/same-as-english.json

@@ -98,6 +98,7 @@
     "WX",
     "audio {state}",
     "dB",
+    "fire confidence filter|Nominal+",
     "fire confidence|nominal",
     "ft",
     "hPa",
@@ -120,6 +121,7 @@
     "{value} KM",
     "{value} KM/H",
     "{value} KM/S",
+    "{value} MW",
     "ΔE",
     "ΔN",
     "▲ {frp} MW"
@@ -168,9 +170,9 @@
     "MM",
     "NVG",
     "REC",
-    "SRC {value}",
     "S2 GhostMaps",
     "S2 · {name}",
+    "SRC {value}",
     "Sentinel-2",
     "Techno",
     "Trance",
@@ -195,6 +197,7 @@
     "{type}  SPD: {speed}  HDG: {heading}",
     "{value} KM",
     "{value} KM/S",
+    "{value} MW",
     "ΔE",
     "ΔN",
     "▲ {frp} MW"