feat: extend Telemetry Off to reachable 0x3F8 + 0x3FD mux1 flags (experimental)

[hypery11]

Extends the existing Telemetry Off flag (assist_telemetry_off) from a single bit to the full reachable set of telemetry-enable flags, and exposes it on the ESP32 dashboard. Source: ev-open-can-tools disable-telemetry.json (GPL-3.0).

⚠️ Experimental & unverified. It clears only the telemetry flags on frames this tool actually reaches (Chassis/Party). It does not cover the Vehicle-bus ECU log-upload family and does not guarantee reduced detection or any ban protection — and the UI says exactly that.

Bits cleared

• 0x3F8: 19 (ClipParked), 42 (Clip), 43 (Trip), 44 (RoadSegment), 55 (ClipStartStop)
• 0x3FD mux1: 48 (CabinCamera), 50 (autopilotTelemetryInChina)

Deliberately out of scope (documented in-code, not silently dropped)

• 0x389 bits 13/34/35 — would require recomputing the counter + checksum; deferred to avoid emitting invalid frames.
• 0x3B3 + ~11 *_alertMatrix ECU-log-upload frames (0x340/341/342/360/3BA/3C0/3C8/3CD/3CE/3CF) — on the Vehicle CAN bus this tool doesn't reliably tap; reaching them needs Vehicle-bus access first.

Changes

• Flipper + ESP32 0x3F8 and 0x3FD-mux1 handlers clear the reachable bits under the flag.
• prefs.cpp: NVS teloff. web_dashboard.cpp: "Telemetry Off (experimental)" toggle with the honesty hint. test_fsd_core.c: test_telemetry_off. 494 host tests pass; ESP32 builds clean.
• Stacked on feat: opt-in Right-Hand Drive override (0x3F8 bit41), #66 #146; base retargets to main once that merges.
• Not car-validated.