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.

1 files changed, 36 insertions, 17 deletions

diff --git a/modules/core/core-bundle.js b/modules/core/core-bundle.js
index c06af5f..d7d9d61 100644
--- a/modules/core/core-bundle.js
+++ b/modules/core/core-bundle.js
@@ -6431,7 +6431,11 @@ Only output XML function calls for tool tasks. If no tool is needed, answer norm
                         if (helpEntry) {
                             this.terminal.print(helpEntry, 'info');
                         } else {
-                            this.terminal.print(`No help available for ${cmd}`, 'warning');
+                            // MAINT-019: a registered command with no help line answered "No help
+                            // available", which reads as if the command does not exist. Name the
+                            // module that owns it so the user knows where to look.
+                            const owner = allCommands[cmd];
+                            this.terminal.print(`${cmd} — registered by ${owner}, which publishes no help line for it. Try: help`, 'warning');
                         }
                     } else {
                         this.terminal.print(`No help available for ${cmd}`, 'warning');
@@ -10045,13 +10049,21 @@ buildSystemPrompt() {
                 try {
                     var fs = this.terminal.fs;
                     if (fs) {
-                        var index = fs.fsReadJSON('/skills/index.json') || {};
-                        var lessonKeys = Object.keys(index).filter(function(k) { return k.indexOf('loop-lesson-') === 0; });
+                        // MAINT-020: lessons live in /lessons, not in /skills — writing them into
+                        // the skills directory made auto-generated lessons show up as skills.
+                        var index = fs.fsReadJSON('/lessons/index.json') || {};
+                        var lessonKeys = Object.keys(index);
+                        if (lessonKeys.length === 0) {
+                            // one-release fallback for lessons written by older builds
+                            var legacy = fs.fsReadJSON('/skills/index.json') || {};
+                            lessonKeys = Object.keys(legacy).filter(function(k) { return k.indexOf('loop-lesson-') === 0; });
+                        }
                         if (lessonKeys.length > 0) {
                             var recentLessons = lessonKeys.sort().slice(-3);
                             var lessonTexts = [];
                             for (var li = 0; li < recentLessons.length; li++) {
-                                var lc = fs.readFile('/skills/' + recentLessons[li] + '.md');
+                                var lc = fs.readFile('/lessons/' + recentLessons[li] + '.md')
+                                    || fs.readFile('/skills/' + recentLessons[li] + '.md');
                                 if (lc) {
                                     var excerpt = lc.substring(0, 300);
                                     lessonTexts.push('[Lesson: ' + recentLessons[li] + '] ' + excerpt);
@@ -13187,23 +13199,30 @@ buildSystemPrompt() {
                 var suggestion = suggestions.join('\n');
                 try {
                     var fs = this.terminal.fs;
-                    var index = fs.fsReadJSON('/skills/index.json') || {};
-                    var autoSkills = Object.entries(index).filter(function(e) { return (e[1].tags || []).indexOf('auto-improvement') !== -1; });
-                    // One-time cleanup: remove all existing loop-lesson files on first run
+                    // MAINT-020: lessons are kept in /lessons with their own index; /skills is
+                    // reserved for real skills the user or the agent creates deliberately.
+                    try { fs.mkdirRecursive('/lessons'); } catch (ex) {}
+                    var index = fs.fsReadJSON('/lessons/index.json') || {};
+                    var autoSkills = Object.entries(index);
+                    // One-time migration: earlier builds wrote loop-lesson-* into /skills.
                     if (!this._loopLessonCleaned) {
                         this._loopLessonCleaned = true;
-                        autoSkills.forEach(function(e) {
-                            try { fs.unlink('/skills/' + e[0] + '.md'); } catch (ex) {}
-                            delete index[e[0]];
-                        });
-                        autoSkills = [];
+                        try {
+                            var sIdx = fs.fsReadJSON('/skills/index.json') || {};
+                            Object.keys(sIdx).filter(function(k) { return k.indexOf('loop-lesson-') === 0; })
+                                .forEach(function(k) {
+                                    try { fs.unlink('/skills/' + k + '.md'); } catch (ex) {}
+                                    delete sIdx[k];
+                                });
+                            fs.fsWriteJSON('/skills/index.json', sIdx);
+                        } catch (ex) {}
                     }
                     // Age limit: remove lessons older than 24h
                     var now = Date.now();
                     autoSkills = autoSkills.filter(function(e) {
                         var created = new Date(e[1].created).getTime();
                         if (now - created > 86400000) {
-                            try { fs.unlink('/skills/' + e[0] + '.md'); } catch (ex) {}
+                            try { fs.unlink('/lessons/' + e[0] + '.md'); } catch (ex) {}
                             delete index[e[0]];
                             return false;
                         }
@@ -13215,17 +13234,17 @@ buildSystemPrompt() {
                     // FIFO rotation: if at cap, delete oldest before creating
                     if (!isDuplicate && autoSkills.length >= 3) {
                         var oldest = autoSkills[0];
-                        try { fs.unlink('/skills/' + oldest[0] + '.md'); } catch (ex) {}
+                        try { fs.unlink('/lessons/' + oldest[0] + '.md'); } catch (ex) {}
                         delete index[oldest[0]];
                         autoSkills.shift();
                     }
                     if (!isDuplicate) {
                         var skillName = 'loop-lesson-' + Date.now();
                         var content = '---\nname: ' + skillName + '\ndescription: Auto-saved from agent loop anomaly detection\ntags: [auto-improvement, agent-loop, auto]\ncategory: system\n---\n## Anomalies Detected\n\n' + JSON.stringify(anomalies, null, 2) + '\n\n## Suggestions\n\n' + suggestion + '\n\n## Context\n- Profile: ' + (this._activeLoopProfile ? this._activeLoopProfile.name : 'none') + '\n- Turns: ' + result.toolTurns + '\n- Tools used: ' + toolLog.map(function(t) { return t.name; }).join(', ');
-                        fs.mkdirRecursive('/skills');
-                        fs.writeFile('/skills/' + skillName + '.md', content);
+                        fs.mkdirRecursive('/lessons');
+                        fs.writeFile('/lessons/' + skillName + '.md', content);
                         index[skillName] = { name: skillName, description: 'Auto-saved loop lesson', tags: ['auto-improvement', 'agent-loop', 'auto'], category: 'system', created: new Date().toISOString(), updated: new Date().toISOString(), anomalyTypes: anomalyTypes };
-                        fs.fsWriteJSON('/skills/index.json', index);
+                        fs.fsWriteJSON('/lessons/index.json', index);
                     }
                 } catch (e) { /* VFS not available */ }
                 var msg = '💡 Self-improvement: ' + anomalies.length + ' anomaly(ies)';