fix(lsp): address codex review round 3

Final review pass on the local provider:
- Tear the instance down when `initialize` REJECTS (utf-8 negotiation, malformed
  result), not only on abort, so a permanently-rejecting `ready` is never pooled.
- Use the group-aware SIGKILL on a framing failure so helpers are reached.
- Validate maxMessageBytes and maxDocumentBytes positive at load alongside the
  other byte caps.
- Fix the location renderer's outside-workspace check to match a `..` segment
  exactly, so an in-workspace path like `..generated/a.ts` stays relative.
- Document the accepted ancestor-directory symlink-swap TOCTOU under the
  trusted-host model (O_NOFOLLOW guards only the final component).

packages/lsp/lsp-local/src/index.ts

@@ -114,8 +114,12 @@ export function apply(ctx: Context, config: Config): void {
   // nonpositive value would let a server that ignores shutdown hang disposal forever. Fail at load.
   assertPositiveInteger('shutdownTimeoutMs', resolved.shutdownTimeoutMs)
   assertPositiveInteger('killGraceMs', resolved.killGraceMs)
-  // A nonpositive stderr cap defeats the retained-tail bound (`slice(-0)` keeps everything).
+  // Byte caps must be positive: a nonpositive stderr cap defeats the retained-tail bound
+  // (`slice(-0)` keeps everything), `maxMessageBytes: 0` makes every response fatal, and a bad
+  // document cap fails later in the read path instead of at load.
   assertPositiveInteger('maxStderrBytes', resolved.maxStderrBytes)
+  assertPositiveInteger('maxMessageBytes', resolved.maxMessageBytes)
+  assertPositiveInteger('maxDocumentBytes', resolved.maxDocumentBytes)
   const childEnv = buildChildEnv(resolved.env)
   // Resolve the executable eagerly so a misconfigured command fails at load, not on first query.
   const executable = resolveExecutable(resolved.command, childEnv)