chore(claude): deny agent writes to the treesitter grammars

tools/ts-wasm/build.sh compiles straight out of the working trees under
/var/mnt/data/projects/treesitter, so editing a grammar source or a
highlights query silently changes the wasm and native artefacts.

The divergence is invisible: treesitter is not itself a repo, so the
cross-repo status sweeps report it as "not a git repo" and never descend
into the ~49 sub-checkouts. A stray edit shows only in that one
checkout's git status, which nothing routinely reads, and survives until
someone re-clones.

Guards the plausible accident — hand-editing a grammar while chasing a
highlighting bug. It does not constrain Bash, so it is a guardrail
against silent divergence rather than a hard boundary.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.claude/settings.json

@@ -39,6 +39,8 @@
       "Bash(awk *)"
     ],
     "deny": [
+      "Edit(//var/mnt/data/projects/treesitter/**)",
+      "Write(//var/mnt/data/projects/treesitter/**)",
       "Bash(rm -rf /*)",
       "Bash(rm -rf ~*)",
       "Bash(rm -rf $HOME*)",