docs(state): mark M1 merged, clear in-progress

Post-merge bookkeeping so the next session's TODO is accurate. Next: M2
(WiFi manager + on-device REST API).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

state/TODO.md

@@ -5,10 +5,7 @@
 
 ## In progress
 
-- [ ] M1 Firmware recording core - code complete on `feature/fw-recorder-core`, in PR.
-      I2S/PDM mic capture -> WAV on microSD, button start/stop, LED status, sidecar JSON
-      metadata. Not yet compiled locally (no PlatformIO here) or hardware-verified; relies
-      on Forgejo Actions CI to build both board profiles.
+- [ ] (nothing active - M2 is next)
 
 ## Pending (roughly in build order)
 
@@ -34,6 +31,8 @@
 
 ## Done
 
+- [x] M1 Firmware recording core - mic capture to WAV on SD + button/LED + metadata
+      (merged: PR #1 `feature/fw-recorder-core`, 2026-07-03). Not yet hardware-verified.
 - [x] M0 Scaffold - repo, licences, state docs, BOM, OpenAPI, skeletons, CI
       (merged to `main`, 2026-07-03)
 - [x] Create Forgejo repo `laurence/openscribe` (public, main) - 2026-07-03