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.

docs/ddd/hardware-platform-domain-model.md

@@ -14,7 +14,7 @@ This document defines the system using [Domain-Driven Design](https://martinfowl
 | 4 | [Aggregation](#4-aggregation-context) | Server-side CSI frame reception, timestamp alignment, multi-node feature fusion | [ADR-012](../adr/ADR-012-esp32-csi-sensor-mesh.md) | `crates/wifi-densepose-hardware/src/esp32/` |
 | 5 | [Provisioning](#5-provisioning-context) | NVS configuration, firmware lifecycle, fleet management, deployment presets | [ADR-044](../adr/ADR-044-provisioning-tool-enhancements.md) | `firmware/esp32-csi-node/provision.py` |
 
-All firmware paths are relative to the repository root. Rust crate paths are relative to `rust-port/wifi-densepose-rs/`.
+All firmware paths are relative to the repository root. Rust crate paths are relative to `v2/`.
 
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