feat: calibration/ corpus + scenarii regresie FSM

- calibration/frames/: 16 PNG-uri ground-truth numite {ts}_{color}.png,
  copiate din logs/fires (izolate de samples/ și logs/fires/ care se pot goli)
- calibration/calibration_labels.json: mutat din samples/, curățat de entries
  cu fișiere inexistente, extins la acoperire completă 7 culori → 16/16 PASS
- calibration/scenarios.json: 8 secvențe FSM (BUY/SELL full cycle, phase_skip,
  catchup, post-fire suppression) pe frame-uri reale
- tests/test_scenarios_regression.py: parametrizat pe scenarios.json, asertează
  color+state+reason+trigger+alerts+scheduler prin pipeline-ul
  Detector → _handle_tick
- docs: README + CLAUDE reflectă noua structură, incidentul 2026-04-20/21
  (pixel saturat UNKNOWN → FSM blocat în PRIMED → polling continuu) +
  troubleshooting pentru trigger UNKNOWN

Pytest: 184 → 192 passed (+8 scenarii regresie).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

calibration/README.md

@@ -0,0 +1,49 @@
+# calibration/ — frame corpus for validation & regression
+
+Two artifacts, one frame pool:
+
+- `calibration_labels.json` — per-frame color labels. Used by
+  `atm validate-calibration` to check the current palette classifies known-good
+  dots correctly before a live session.
+- `scenarios.json` — ordered frame sequences per FSM scenario (full cycle,
+  phase skip, catchup, post-fire suppression). Consumed by
+  `tests/test_scenarios_regression.py` which runs each sequence through the
+  full `Detector → _handle_tick` pipeline and asserts color, FSM reason/state,
+  emitted alerts, and scheduler on/off.
+
+Frames live in `calibration/frames/` and are self-contained: purging
+`logs/fires/` or `samples/` does not break either artifact.
+
+## calibration_labels.json schema
+
+## Schema
+
+A JSON array of entries. Each entry:
+
+| Field      | Type    | Required | Description                                                    |
+|------------|---------|----------|----------------------------------------------------------------|
+| `path`     | string  | yes      | Path to a PNG frame (relative to CWD or absolute).             |
+| `expected` | string  | yes      | Expected color name: one of `turquoise`, `yellow`, `dark_green`, `dark_red`, `light_green`, `light_red`, `gray`. |
+| `note`     | string  | no       | Freeform annotation; shown in SUGGESTIONS output.              |
+
+## Usage
+
+```bash
+atm validate-calibration calibration/calibration_labels.json
+```
+
+Exit codes:
+- `0` — every sample PASS
+- `1` — one or more FAIL
+- `2` — label file missing or malformed JSON
+
+## Adding new samples
+
+1. Find a screenshot in `logs/fires/` whose dot color you can verify by eye.
+2. **Copy it into `calibration/frames/`** — this directory is self-contained so
+   `logs/fires/` and `samples/` can be emptied without breaking validation.
+3. Append an entry with `path` (pointing to `calibration/frames/...`),
+   `expected`, and an optional `note`.
+4. Re-run validation. If it FAILs, the SUGGESTIONS section will tell you the
+   RGB distance between the observed pixel and the expected color's center —
+   use that as input for `atm calibrate`.