chore(repo): move v1/ → archive/v1/ + add archive/README.md (#430)

The Rust port at v2/ has been the primary codebase since the rename
in #427. The Python implementation at v1/ is no longer the active
target; the only load-bearing path is the deterministic proof bundle
at v1/data/proof/ (per ADR-011 / ADR-028 witness verification).

Move the whole Python tree into archive/v1/ and document the policy
in archive/README.md: no new features, bug fixes only when they affect
a still-load-bearing path (currently just the proof), CI continues to
verify the proof on every push and PR.

Path references updated in 26 files via path-pattern sed (only
matches v1/<known-child> patterns, never bare v1 or API URLs like
/api/v1/). Two double-prefix typos (archive/archive/v1/) caught and
hand-fixed in verify-pipeline.yml and ADR-011.

Validated:
- Python proof verify.py imports cleanly at archive/v1/data/proof/
  (numpy/scipy still required; CI installs requirements-lock.txt
  from archive/v1/ now)
- cargo test --workspace --no-default-features → 1,539 passed,
  0 failed, 8 ignored (unaffected by Python tree relocation)
- ESP32-S3 on COM7 untouched (no firmware paths changed)

After-merge: contributors should re-run any local `python v1/...`
commands as `python archive/v1/...` (CLAUDE.md and CHANGELOG already
updated).

archive/v1/src/api/routers/auth.py

@@ -0,0 +1,32 @@
+"""
+Authentication router for WiFi-DensePose API.
+Provides logout (token blacklisting) endpoint.
+"""
+
+import logging
+from typing import Optional
+
+from fastapi import APIRouter, Request, HTTPException, status
+
+from src.api.middleware.auth import token_blacklist
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(prefix="/auth", tags=["auth"])
+
+
+@router.post("/logout")
+async def logout(request: Request):
+    """Logout by blacklisting the current Bearer token."""
+    auth_header = request.headers.get("authorization")
+    if not auth_header or not auth_header.startswith("Bearer "):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Missing or invalid Authorization header",
+        )
+
+    token = auth_header.split(" ", 1)[1]
+    token_blacklist.add_token(token)
+    logger.info("Token blacklisted via /auth/logout")
+
+    return {"success": True, "message": "Token revoked"}