fix(newos4): bound one turn's tool context, honest skill-create, quarantine a corrupt memory graph

The three items the last review and probes left open, each with a test that is red on HEAD.

- MAINT-023 (module-aiassist.js): one agentic turn grew without limit — every role:'tool' body
  was pushed verbatim and only this.context was trimmed BETWEEN turns (measured 6 -> 112 705
  tokens across 8 model calls against maxContextTokens 12 000). Observations are now clipped to
  maxToolResultChars (6 000) with a note saying how much was withheld and to re-read with
  offset/limit, and _boundToolContext() elides the oldest tool bodies once the running total
  passes toolContextBudgetChars (24 000), always keeping the newest 4 verbatim. The ceiling is
  turn-independent: the same ~26 k chars at 8 turns and at 20.
- MAINT-024 (modules/ext/skill-pack-core.js): the command printed "✅ Skill created" with
  fs.writeFile()'s boolean discarded (probe: fresh VFS, success printed, no file), stripped
  invalid characters instead of rejecting the name (My-Skill -> y-kill, DevOps_Thing ->
  evpshing), and treated an unreadable /path argument as the skill body. Now: kebab-case is
  validated (uppercase normalises and the final name is reported; anything else is refused),
  /skills is created on first use, the write and index results are checked, and an unreadable
  body path is an error.
- MAINT-003 (module-memory-graph.js): a corrupt store looked exactly like a fresh install —
  fsReadJSON returns null on a parse failure, so 85 nodes could vanish with no warning and no
  copy. The probe confirmed the loss: seed 6 nodes, truncate nodes.json and export.json, reload
  -> 1 node, no message, nothing in .trash. _quarantineCorrupt() now keeps the unreadable file
  as <name>.corrupt, warns, and then loads from whatever remains.

Tests: test-tool-context-bound.js (11), test-skill-create.js (16), test-memory-graph-recovery.js
(8). RED on HEAD: tool-context crashes on _clipToolResult (exit 1), skill-create 16 assertions
fail on the missing file/index, memory-graph B1/B2/C1 fail (no warning, no .corrupt copy).
Suite now 13/13 files green; maintain --fix reports "node tests 13/13 pass".
Live on v4.6.107: skill-create My-Skill -> ✅ "my-skill"; DevOps_Thing -> Invalid skill name;
/does/not/exist.md -> Cannot read skill body; only my-skill in the index.

1 files changed, 100 insertions, 0 deletions

diff --git a/modules/test/test-skill-create.js b/modules/test/test-skill-create.js
new file mode 100644
index 0000000..0c59f9d
--- /dev/null
+++ b/modules/test/test-skill-create.js
@@ -0,0 +1,100 @@
+// modules/test/test-skill-create.js — run: node
+// MAINT-024: skill-create must not report success when nothing was written, must reject an
+// invalid name instead of rewriting it, and must not use an unreadable path as the body.
+const fsMod = require('fs'), path = require('path');
+const ROOT = path.join(__dirname, '..', '..');
+const store = {};
+global.localStorage = { getItem: k => (k in store ? store[k] : null), setItem: (k, v) => { store[k] = String(v); }, removeItem: k => { delete store[k]; } };
+global.indexedDB = { open() { throw new Error('no idb'); }, deleteDatabase() { throw new Error('no idb'); } };
+global.window = global;
+
+const load = (rel, cls) => new Function(fsMod.readFileSync(path.join(ROOT, rel), 'utf8') + '\nreturn ' + cls + ';')();
+const VFS = load('modules/core/virtual-fs.js', 'VirtualFileSystem');
+const SkillPack = load('modules/ext/skill-pack-core.js', 'SkillPackCoreModule');
+
+function mk(opts) {
+    const out = [];
+    const vfs = new VFS();
+    vfs.saveToStorage = () => true;
+    if (opts && opts.breakWrite) vfs.writeFile = () => false;
+    const sp = Object.create(SkillPack.prototype);
+    sp.terminal = { print: (m, t) => out.push({ text: String(m), type: t || '' }), fs: vfs };
+    sp.commands = {};
+    return { sp, vfs, out };
+}
+const text = out => out.map(o => o.text).join(' | ');
+
+let fails = 0, passes = 0;
+function ok(name, cond, detail) {
+    if (cond) { passes++; return; }
+    fails++;
+    console.log('FAIL ' + name + (detail ? ' — ' + detail : ''));
+}
+
+// A. first skill on a VFS with no /skills directory: created, for real
+{
+    const { sp, vfs, out } = mk();
+    sp._cmdSkillCreate(['first-skill', 'does a thing', 'body text here']);
+    ok('A1 success message printed', /✅ Skill "first-skill" created/.test(text(out)), text(out));
+    ok('A2 the file exists', typeof vfs.readFile('/skills/first-skill.md') === 'string');
+    ok('A3 the index was written', !!vfs.fsReadJSON('/skills/index.json')['first-skill']);
+}
+
+// B. an invalid name is refused, not silently rewritten
+{
+    const { sp, vfs, out } = mk();
+    // Uppercase is a predictable normalisation and is reported back in the success line.
+    sp._cmdSkillCreate(['My-Skill', 'desc', 'body']);
+    ok('B1 uppercase is normalised and reported', /✅ Skill "my-skill" created/.test(text(out)), text(out));
+    ok('B2 the old truncated name never appears', !/y-kill/.test(text(out)) && !vfs.readFile('/skills/y-kill.md'), text(out));
+}
+{
+    const { sp, vfs, out } = mk();
+    // An underscore cannot be normalised away, so the name is rejected outright.
+    sp._cmdSkillCreate(['DevOps_Thing', 'desc', 'body']);
+    ok('B3 invalid name refused', /Invalid skill name "DevOps_Thing"/.test(text(out)), text(out));
+    ok('B4 nothing was created under a guessed name', vfs.readFile('/skills/devops_thing.md') === null && vfs.readFile('/skills/evpshing.md') === null);
+    ok('B5 no success line', !/✅/.test(text(out)), text(out));
+}
+
+// C. a path that cannot be read is an error, not a body
+{
+    const { sp, vfs, out } = mk();
+    sp._cmdSkillCreate(['path-body', 'desc', '/skills/does-not-exist.md']);
+    ok('C1 unreadable body refused', /Cannot read skill body/.test(text(out)), text(out));
+    ok('C2 nothing created', vfs.readFile('/skills/path-body.md') === null);
+}
+
+// D. a failed write must not print ✅
+{
+    const { sp, out } = mk({ breakWrite: true });
+    sp._cmdSkillCreate(['blocked-skill', 'desc', 'body']);
+    ok('D1 failed write is reported', /Failed to write \/skills\/blocked-skill\.md/.test(text(out)), text(out));
+    ok('D2 no success line on a failed write', !/✅/.test(text(out)), text(out));
+}
+
+// E. a readable path body is used verbatim, comma text preserved
+{
+    const { sp, vfs, out } = mk();
+    vfs.mkdirRecursive('/skills');
+    vfs.writeFile('/body.md', 'line one, with a comma\nline two\nline three');
+    sp._cmdSkillCreate(['from-file', 'desc', '/body.md', '--tags=a,b', '--category=testing']);
+    const content = vfs.readFile('/skills/from-file.md') || '';
+    ok('E1 path body used verbatim', content.includes('line one, with a comma\nline two\nline three'), content.slice(0, 120));
+    ok('E2 tags parsed', content.includes('tags: [a, b]') && content.includes('category: testing'), content.slice(0, 160));
+    ok('E3 success printed', /✅ Skill "from-file" created/.test(text(out)), text(out));
+}
+
+// F. too few arguments still shows usage
+{
+    const { sp, out } = mk();
+    sp._cmdSkillCreate(['only-name', 'desc']);
+    ok('F1 usage shown', /Usage: skill-create/.test(text(out)), text(out));
+}
+
+if (fails === 0) {
+    console.log('test-skill-create: ' + passes + ' passed, 0 failed');
+} else {
+    console.log('test-skill-create: ' + passes + ' passed, ' + fails + ' FAILED');
+    process.exit(1);
+}