v1.3.0: Add 14 keyfob protocols (8 ProtoPirate + 6 Flipper-ARF), fix KeeLoq overflow

Brings KAT to 32 protocol decoders. Ported from the ProtoPirate reference and the
D4C1-Labs/Flipper-ARF firmware:

  ProtoPirate (8): Kia V7, Ford V1, Ford V2, Ford V3, Chrysler V0, Honda Static,
  Honda V1, Land Rover V0.
  Flipper-ARF (6): Toyota, Land Rover RKE, Mazda Siemens, BMW CAS4,
  Porsche Cayenne, PSA2.

Each decoder is gated (CRC / checksum / fixed markers / frame structure) so it
cannot false-match existing protocols; every previously-decoding IMPORTS capture
decodes unchanged. Real-capture decodes added for Ford V3 (LDV T80), Honda Static
(Honda), Toyota (Camry NRZ variant), and PSA2 (Groupe PSA, serial 0x99EB25); the
rest are validated by encode/decode round-trip and synthetic-frame tests.

Also fixes a debug-only underflow panic in keeloq_common::keeloq_decrypt
(15 - r underflowed; now wrapping_sub to match the reference's unsigned wrap;
release behavior unchanged).

Adds per-protocol docs, updates the README protocol table, capture metadata
(encoding / RF / encryption), make-suggestion mapping, and CHANGELOG.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JEfaKqzB3T4qsrybwfEi73

docs/mazda_siemens.md

@@ -0,0 +1,70 @@
+---
+layout: default
+---
+
+# Mazda Siemens Protocol
+
+**Rust module:** `src/protocols/mazda_siemens.rs`
+**Reference:** `Flipper-ARF lib/subghz/protocols/mazda_siemens.c`
+
+## Overview
+
+The Siemens/VDO keyfob cipher used on some Mazda vehicles — a DIFFERENT protocol from KAT's existing
+"Mazda V0" (Pandora) decoder, even though both ride a 250/500 µs pair-based stream at 433.92 MHz FM. The
+decoder is pair-based: `feed()` ignores `level` and interprets raw durations in pairs (`process_pair`),
+collecting bits with *inverted* polarity (`state_bit == 0` → stored 1). 64-bit frame.
+
+Siemens obfuscation (`mazda_xor_deobfuscate`): parity-dependent XOR mask, then bit-deinterleave of bytes
+5/6. The inner Siemens cipher's plaintext is left as-is (no key); only this obfuscation/interleave layer
+is reversed. The gate is an additive checksum `sum(data[0..7]) == data[7]`, plus the structural
+preamble/sync/bit-count constraints, which keeps it from false-matching other 250/500 µs Manchester
+protocols.
+
+> **Note:** KAT's existing "Mazda V0" decoder implements the same algorithm and keeps first-match
+> priority, so on a shared frame Mazda V0 fires first.
+
+## Timing
+
+| Parameter   | Value  | Notes                       |
+|-------------|--------|-----------------------------|
+| Short       | 250 µs | ±100 µs (te_delta)          |
+| Long        | 500 µs | ±100 µs                     |
+| Min bits    | 64     |                             |
+| Preamble    | ≥13 short/short pairs |              |
+| Completion  | 80–105 collected bits |              |
+
+## Frame Layout (64 bits / 8 bytes, after deobfuscation)
+
+The 14-byte buffer's leading sync byte is discarded, leaving 8 bytes:
+
+- **serial:** `data >> 32` (32-bit)
+- **button:** `(data >> 24) & 0xFF` — Lock=0x10, Unlock=0x20, Trunk=0x40
+- **counter:** `(data >> 8) & 0xFFFF` (16-bit)
+- **byte 7:** additive checksum of bytes 0–6
+
+## RF
+
+- **Encoding:** pair-based Manchester (inverted polarity), 250/500 µs
+- **RF modulation:** FM
+- **Encryption:** Siemens obfuscation (parity XOR + bit-interleave); gated on the additive checksum
+- **Frequencies:** 433.92 MHz only
+
+## Decoder Steps
+
+1. **Reset** — a short pulse begins the preamble.
+2. **PreambleSave/PreambleCheck** — count short/short pairs (≥13); a short→long transition seeds the leading sync bit (a 1) and enters data.
+3. **DataSave/DataCheck** — process duration pairs into bits; on a non-matching pair, run `check_completion` (discard sync byte, deobfuscate, validate additive checksum) and emit.
+
+## Encoder
+
+Supported (`subghz_protocol_encoder_mazda_siemens_get_upload`). Increments the counter byte, recomputes
+the checksum, obfuscates (interleave + XOR), then emits a 12-byte 0xFF preamble, a 50 ms gap, `0xFF 0xFF
+0xD7`, the 8 obfuscated bytes transmitted as `255 − byte`, a `0x5A` tail, and a trailing 50 ms gap.
+Manchester per byte: bit 1 → (H,L), bit 0 → (L,H) at te_short. As in the C, the decoder and encoder are
+not a clean raw-timing round-trip pair (the encoder targets a TX upload).
+
+## Validation
+
+Verified by an encode→decode round-trip / synthetic-frame check (no local capture available). Unit tests
+cover the obfuscate/deobfuscate XOR+interleave cipher layer (a true inverse, both parity branches), the
+field layout, and the TX upload smoke test.