fix(sync): stop syncCursor deleting the user's .cursor/ state

[MANVENDRA-github]

The bug

syncCursor called rmGenerated on the whole .cursor/ tree, while syncClaude, syncCodex, and syncOpenCode each remove only the subdirectories they generate.

So npm run sync deleted every file a user keeps in .cursor/ — including .cursor/environment.json, Cursor's own background-agent config.

Demonstrated by planting files and running sync, before the fix:

.claude/settings.local.json   SURVIVED
.claude/other/user.txt        SURVIVED
.cursor/environment.json      DELETED     ← Cursor's own config
.cursor/my-own-rule.mdc       DELETED

The README already promised the opposite:

An adapter deletes only the subdirectories it generates … never the parent .claude/.

And syncCursor's own docstring said agents get an agentry- prefix "to avoid collisions with the user's own Cursor agents" — agents the same function had just deleted three lines earlier. The prefix only ever protected the install path.

The guard had drifted the same way

protect-generated-dirs listed .cursor/ and .codex/ wholesale, so it blocked edits to:

• .cursor/environment.json — which sync (after this fix) preserves
• .codex/config.toml — which sync always preserved, and which the README names as Codex's per-user state

A guard that refuses an edit the engine would have kept is as wrong as one that permits an edit the engine will destroy.

The fix

syncCursor wipes .cursor/agents/ and .cursor/rules/ only. .cursor/mcp.json joins .mcp.json and opencode.json under D20 — written when MCP sources exist, never deleted, may carry the user's own servers.

The hook's GENERATED list now names the wiped subdirectories exactly:

".claude/agents/", ".claude/skills/", ".claude/commands/", ".claude/rules/", ".claude/hooks/",
".claude-plugin/",
".cursor/agents/", ".cursor/rules/",
".codex/agents/skills/",
".opencode/agents/", ".opencode/skills/", ".opencode/commands/",

Verification — the hook and the engine must describe the same set

Planted a file at all 18 harness paths, ran sync, recorded what survived, and compared it against the hook's exit code. Correct pairing is wiped → BLOCK, preserved → allow.

path                                   sync       hook     agree?
.claude/agents/zz-user.md              wiped      BLOCK    yes
.claude/skills/zz/SKILL.md             wiped      BLOCK    yes
.claude/rules/zz.md                    wiped      BLOCK    yes
.claude/hooks/zz.js                    wiped      BLOCK    yes
.claude/settings.local.json            preserved  allow    yes
.claude/zz-user.json                   preserved  allow    yes
.cursor/agents/zz.md                   wiped      BLOCK    yes
.cursor/rules/zz.mdc                   wiped      BLOCK    yes
.cursor/environment.json               preserved  allow    yes
.cursor/mcp.json                       preserved  allow    yes
.codex/agents/skills/zz/SKILL.md       wiped      BLOCK    yes
.codex/config.toml                     preserved  allow    yes
.opencode/agents/zz.md                 wiped      BLOCK    yes
.opencode/skills/zz/SKILL.md           wiped      BLOCK    yes
.opencode/commands/zz.md               wiped      BLOCK    yes
.opencode/zz-user.json                 preserved  allow    yes
.mcp.json                              preserved  allow    yes
opencode.json                          preserved  allow    yes

mismatches: 0

Plus the three properties the change could have broken:

• Generated output byte-identical — git diff --numstat -- .cursor → 0 files
• Still idempotent — two consecutive syncs hash identically
• Stale removal still works — deleting skills/caching/ and re-syncing removes .cursor/rules/caching.mdc

$ npm run lint   # PASS
$ npm test       # 243 pass, 0 fail   (was 239)
$ npm run sync   # clean, no drift

README's per-user-state list gains Cursor — it had none to name while sync was deleting it.