docs: restructure TASKS.md into a catalog — one file per task in TASKS/

TASKS.md is now the index (status table, open items, research pointer).
33 files: 32 task files + 1 research facts file. The full take-saga
narrative and all design decisions are preserved verbatim; the catalog
makes the queue readable without opening every task body. Schema and
AGENTS.md updated to reflect the new layout.

TASKS/task-12-master-limiter.md

@@ -0,0 +1,31 @@
+# TASK 12 — Master limiter on the live mix (2026-08-15)
+
+> Catalog: [`TASKS.md`](../TASKS.md) — status and requirements live here.
+
+
+**Queued by the creator during the TRAX discussion:** "should the soundtrack be limited to avoid
+squandering resources / should it cap at 20% / how do the three sound events balance?" Review
+conclusions (all three instincts checked out, only ONE real gap):
+
+- **File size — no guard needed.** `MusicPlayer` uses `MediaFoundationReader`, which **streams from
+  disk** (progressive source): memory is flat (~a few MB) regardless of file size; CPU negligible.
+- **20% cap — already enforced by construction.** `MusicPlayer.MusicVolume = 0.20f` + music rides the
+  SAME WASAPI loopback (and therefore the same gain) as game audio, so music:game is always exactly
+  **0.20:1 at any slider position** — it literally cannot rise above 20% of the current desktop volume.
+- **The gap:** `AudioMixer.FillAndMix` summed mic + loopback with **no output ceiling** — mic 100% +
+  loud game/music could pass 0 dBFS and clip the AAC encode.
+
+**Shipped:**
+1. ✅ **`Services/Audio/MasterLimiter.cs`** (pure, unit-tested) — a **−1 dBFS ceiling** (`Ceiling =
+   0.891`), **instant attack per frame** (a hot frame is scaled exactly to the ceiling — no overshoot),
+   **smoothed release** toward unity so loud passages don't pump; gain never exceeds 1 (no boosting).
+   Applied at the end of `AudioMixer.FillAndMix`, right before the pipe write.
+2. ✅ **Unit tests** — over-ceiling frames trimmed to ≤ ceiling; sub-ceiling frames never boosted; gain
+   recovers to unity after the loud frame ends.
+3. ✅ **ONE integration test** (`MasterLimiter_CapsTheLiveMix_OnThePipe`) — real mixer + pipe harness:
+   a 0.95 loopback bed (hotter than the ceiling) is capped to exactly 0.891 on the wire while staying
+   audible.
+4. ✅ **Docs in the same commit** — `ai.md` (go-live audio section), `Services/index.md` (new row).
+
+No changes to `MusicPlayer`, the 0.20 cap, the ducker, or the meter zones. Build 0 warnings.
+