fix(newos4): help names the owner of an undocumented command; loop lessons leave /skills

Two board items plus the context-window close-out.

- MAINT-019 (module-system.js): `help <cmd>` answered "No help available for X" for a command
  that is registered but has no help line, which reads as if the command does not exist. It now
  says "X — registered by <Module>, which publishes no help line for it. Try: help". A command
  that genuinely does not exist still gets the old message.
- MAINT-020 (module-aiassist.js): auto-generated loop lessons were written into /skills with
  their own index entries, so `skill list` filled up with system noise. Lessons now live in
  /lessons with /lessons/index.json; the reader still falls back to legacy loop-lesson-* entries
  in /skills for one release, and the one-time migration deletes them from the skills index.

Verification: test-help-and-lessons.js (10 asserts, includes a lint-style guard that no lesson is
written into /skills). Suite 14/14 files green; maintain --fix "node tests 14/14 pass",
"help coverage 362/362". Live on v4.6.108: `help agent-register` -> "registered by
AgentRegistryModule, which publishes no help line for it"; `help a2a-prune` unchanged;
`help nope-not-real` still "No help available".

MAINT-001 close-out (no code change here): history is capped at 20 messages with a "[context trim]"
marker (first trim at turn 11 in a 60-turn probe), token compression took 80 msgs/8080 tok to
17/2625, and since v4.6.107 one turn's tool bodies are clipped to 6 000 chars each and elided past
24 000 with the newest 4 kept verbatim. Residual, recorded on the board: maxContextTokens is never
sent to the server as num_ctx, so the real window is whatever the endpoint defaults to.

MAINT-018 close-out: not reproducible. Live probes on v4.6.107/108 — `sed -n '1,3p' /probe.txt`
prints lines 1-3, `sed -n "2,4p"` prints 2-4, `grep 'line4'` matches, and the same commands inside
`script /q.sh` print correctly. The "Command not found: for;" symptom belongs to the line-by-line
script runner, which is MAINT-021 and stays open.

0 files changed, 0 insertions, 0 deletions