chore(repo): rename rust-port/wifi-densepose-rs → v2/ (flatten to one level) (#427)

The Rust port lived two directories deep (rust-port/wifi-densepose-rs/)
without any sibling under rust-port/ that warranted the extra level.
Move the whole workspace up to v2/ to match v1/ (Python) at the same
depth and shorten every cd / build command across the repo.

git mv preserves history for all tracked files. 60 files updated for
path references (CI workflows, ADRs, docs, scripts, READMEs, internal
.claude-flow state). Two manual fixes for relative-cd paths in
CLAUDE.md and ADR-043 that became wrong after the depth change
(cd ../.. → cd ..).

Validated:
- cargo check --workspace --no-default-features → clean (after target/
  nuke; the gitignored target/ was carried by the OS rename and had
  hard-coded old paths in build scripts)
- cargo test --workspace --no-default-features → 1,539 passed, 0 failed,
  8 ignored (same totals as pre-rename)
- ESP32-S3 on COM7 → still streaming live CSI (cb #40300, RSSI -64 dBm)

After-merge follow-up: contributors should `rm -rf v2/target` once and
let cargo regenerate from the new path.

examples/happiness-vector/README.md

@@ -159,7 +159,7 @@ The happiness scoring algorithm also exists as a WASM module for on-device execu
 
 ```bash
 # Build the happiness scorer WASM
-cd rust-port/wifi-densepose-rs/crates/wifi-densepose-wasm-edge
+cd v2/crates/wifi-densepose-wasm-edge
 cargo build --bin ghost_hunter --target wasm32-unknown-unknown --release --no-default-features
 
 # Output: target/wasm32-unknown-unknown/release/ghost_hunter.wasm (5.7 KB)
@@ -201,6 +201,6 @@ This system is designed to be privacy-preserving by construction:
 
 - [ADR-065](../../docs/adr/ADR-065-happiness-scoring-seed-bridge.md) — Happiness scoring pipeline architecture
 - [ADR-066](../../docs/adr/ADR-066-esp32-swarm-seed-coordinator.md) — ESP32 swarm with Seed coordinator
-- [exo_happiness_score.rs](../../rust-port/wifi-densepose-rs/crates/wifi-densepose-wasm-edge/src/exo_happiness_score.rs) — WASM edge module (Rust)
+- [exo_happiness_score.rs](../../v2/crates/wifi-densepose-wasm-edge/src/exo_happiness_score.rs) — WASM edge module (Rust)
 - [swarm_bridge.c](../../firmware/esp32-csi-node/main/swarm_bridge.c) — ESP32 firmware swarm bridge
 - [ruview_live.py](../ruview_live.py) — RuView Live dashboard with `--mode happiness`