Server-side tools are unblockable: deny rejects the registered casing, and PreToolUse hooks never fire for them

## Summary
Two related defects that combine to make a server-side tool impossible to block by any user-controllable mechanism (verified on Claude Code 2.1.259, Windows 11).

## Defect 1 — settings schema forces a casing the permission matcher cannot match
A session exposes a tool whose registered name is lowercase `advisor` (visible in the session's own tool schema).
- Adding `"advisor"` to `permissions.deny` is rejected by the settings validator: `Tool names must start with uppercase. Use "Advisor"`.
- Adding `"Advisor"` passes validation but produces the startup warning: `Permission deny rule "Advisor" matches no known tool — check for typos.`
- Verified with a positive control: a deliberately bogus deny entry (`"Zzznotatool"`) produces the identical warning, proving the warning mechanism works and that `Advisor` genuinely matches nothing.

So no spelling both validates and matches: the tool cannot be denied through settings.

## Defect 2 — PreToolUse hooks do not fire for server-side tools
As a fallback we registered a PreToolUse hook with matcher `[Aa]dvisor` (registration confirmed in OTEL telemetry: `hook_registered`, `hook_event: "PreToolUse"`, `hook_matcher: "[Aa]dvisor"`). A deliberate advisor invocation in a test session then executed end-to-end with no block and no hook execution event in telemetry — the tool runs server-side, inside the API request, so it never passes through the client tool pipeline that hooks and permission checks intercept.

## Combined impact
A server-side tool injected into a session cannot be blocked by deny rules (defect 1) or hooks (defect 2) — only by prompt text, which loses to the harness re-injecting the tool's call-it-first instruction each session. Aggravating: the defect-1 startup warning prints only on CLI launches; IDE-extension sessions never surface it, so a non-binding deny rule survives invisibly.

## Expected
Either (a) the schema accepts the registered casing / matching is case-insensitive, and (b) permission rules and PreToolUse hooks cover server-side tools — or session configuration offers a way to exclude an injected server-side tool.

## Environment
Claude Code 2.1.259 · Windows 11 (10.0.26200) · observed in both CLI and VSCode-extension sessions

Start with the settings validator and permission matcher for registered tool names, then trace the PreToolUse hook path for server-side tools. Reproduce with a lowercase `advisor` tool in CLI and VSCode-extension sessions, checking the stated OTEL events and startup warning. Done means the registered tool can be denied and PreToolUse hooks can block it, or session configuration can exclude it.

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