feat: CVM relay stability fix + MCP relay integration tests

Relay disconnect fix (cvm_server.c):
- TLS read timeout reduced from 15s to 1s (short poll loop)
- Ping timer fires every 30s independently of read activity
- Consecutive timeout counter (65s) detects real disconnects
- Handle relay close frames (opcode 0x08) explicitly
- Result: 120s+ stable connection (previously ~37s disconnect cycle)

MCP relay integration tests (17/17 pass via make test-cvm-mcp):
- MCP initialize roundtrip via relay.primal.net
- get_sessions returns session array
- get_usage returns metric/price/step fields
- Non-owner auth rejection (board silently drops)
- Owner control request passes after rejection test

Build fixes:
- Remove display/font/axs15231b/qrcode deps (from display branch, not here)
- Remove local_relay/relay_selector/sync_manager deps (from relay branch)
- Add esp_timer to CMakeLists REQUIRES

Host unit tests: 61/61 pass

1 files changed, 35 insertions, 0 deletions

diff --git a/CHECKLIST-CVM-RELAY.md b/CHECKLIST-CVM-RELAY.md
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+# CVM Relay Stability Checklist
+
+## Pre-flight
+- [x] Create worktree `/home/c03rad0r/esp32-tollgate-cvm-relay`
+- [x] Create branch `feature/cvm-relay-stability` from master
+- [x] Document plan in PLAN-CVM-RELAY.md
+
+## Task 3: Fix Relay Disconnect
+- [x] Modify `cvm_relay_task()` inner loop: 1s TLS read timeout
+- [x] Decouple ping timer from read success
+- [x] Add consecutive-timeout counter for real disconnect detection
+- [x] Handle relay close frames (opcode 0x08)
+- [x] `make test-unit` passes (61/61)
+- [x] Build firmware
+- [x] Lock Board B: `make lock-b PHASE="cvm-relay-stability"`
+- [x] Verify Board B port: `esptool.py --port /dev/ttyACM1 chip_id`
+- [x] Flash Board B via `make flash-b`
+- [x] Monitor serial: confirm WS connected, no disconnect in 120s
+- [ ] Unlock Board B (deferred — may need more testing)
+
+## Task 1: Test get_sessions & get_usage via Relay
+- [x] Write `tests/integration/test-cvm-mcp-relay.mjs`
+- [x] Test: `get_sessions` returns JSON array via relay (0 active sessions)
+- [x] Test: `get_usage` returns metric/price/step fields via relay
+- [x] Both tests PASS on Board B (via `make test-cvm-mcp`)
+
+## Task 2: Test Non-Owner Auth Rejection via Relay
+- [x] Test: non-owner request gets no response (12s wait)
+- [x] Test: owner control request succeeds after non-owner test
+- [x] Both tests PASS on Board B (via `make test-cvm-mcp`)
+
+## Final
+- [x] `make test-unit` — 61 tests pass
+- [x] Commit: 3 commits on feature/cvm-relay-stability
+- [ ] Push to remote (nostr git relay down — will retry later)