docs(research): TM learning tracks + note that the TM-DEB source was deleted

tm-learning-tracks.md covers three things, all marked [FACT]/[INFERENCE]/
[UNKNOWN]:
- Section A: the Tsetlin gun's label is measured against the wrong baseline.
  predX = linearX + cx, so rx = actual - predX = delta - cx, and inside
  tmLearnOne error = residual - predicted = (delta - cx) - cx = delta - 2cx.
  The fixed point is cx = delta/2 -- HALF the correction needed, even with
  perfect Granmo feedback. Fix: store linearX/linearY in TmTrace and train
  on delta. Also: hits zero the label instead of carrying their true
  residual, and the per-clause step is magnitude-blind.
- Section B: what a TM is actually good at (AND-clauses over binary
  literals, readable output) and why this repo suits it -- the gun already
  builds an 83-bit x 10-frame Gray-coded window (870 bits). Includes a
  falsifiable known-rule benchmark proposal.
- Section C: delayed-reward learning belongs to the MOVEMENT layer, not the
  gun. The gun's outcome is delayed but exactly pairable via
  (fireTick, powerBin), so its effective lambda is 1 and discounting would
  only destroy information.

Also records that docs/papers/tm-deb-paper.pdf was deleted by the user as
AI-generated and unverifiable, while the Granmo-based feedback diff in
tm-deb-assessment.md stands on its own.

docs/research/tm-deb-assessment.md

@@ -1,5 +1,17 @@
 # TM-DEB Paper Assessment — Adopt as a fix for the Tsetlin gun?
 
+> **Editorial note — source document deleted.** The paper this file reviews,
+> `docs/papers/tm-deb-paper.pdf`, was **deleted by the user** on the grounds that
+> it is AI-generated and unverifiable (the concrete evidence is catalogued in §2:
+> self-identifying "Generated by Gemini Notebook" provenance, a misattributed
+> reference, an algorithm core rendered as literal `%`, and "Expected" rather
+> than measured results). This assessment file is **kept** because its actionable
+> content — the Granmo Table 2/3 feedback diff (§6) and the prioritised fix list
+> (§6.5) — stands on its own from the *verified* sources
+> (`docs/papers/1804.01508v15.pdf` and `common_libs/guns/tsetlin.nim`) and does
+> not depend on the deleted document. Citations to the deleted PDF are retained
+> only as the record of the review that was performed.
+
 **Issue:** N/A (read-only review requested by orchestrator)
 **Date:** 2026-09-20
 **Paper under review:** `docs/papers/tm-deb-paper.pdf` — "Temporal Credit Assignment in Tsetlin Machines via Discounted Eligibility Experience Buffers (TM-DEB)"