✨ feat(kebab-mcp): doctor tool (fb-30)

Second tool — `doctor` (no input args, returns doctor.v1 JSON via
kebab_app::doctor_with_config_path). Mirrors schema tool's manual-dispatch
pattern: Tool::new entry in list_tools, match arm in call_tool, per-tool
module in tools/doctor.rs.

doctor_with_config_path takes Option<&Path> (not &Config), so KebabAppState
is extended with config_path: Option<PathBuf>. All existing callers
(initialize.rs, tools_call_schema.rs, serve_stdio_async) pass None for now;
Plan Task 10 (Cmd::Mcp wiring) will thread the actual --config path through.
doctor_with_config falls back to XDG default when config_path is None —
same behavior as bare `kebab doctor`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-mcp/src/tools/doctor.rs

@@ -0,0 +1,28 @@
+//! `doctor` tool — wraps `kebab_app::doctor_with_config_path`.
+//! Input: {} (no args). Output: doctor.v1 JSON.
+//!
+//! `doctor_with_config_path(Option<&Path>)` re-reads config from disk so
+//! the report reflects the live file state. We forward `config_path` from
+//! `KebabAppState` so `--config <path>` users see results for their file;
+//! callers that pass `None` fall back to the XDG default (same as the CLI
+//! bare `kebab doctor`).
+
+use rmcp::model::CallToolResult;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+use crate::error::{to_tool_error, to_tool_success};
+use crate::state::KebabAppState;
+
+#[derive(Debug, Default, Deserialize, Serialize, JsonSchema)]
+pub struct DoctorInput {}
+
+pub fn handle(state: &KebabAppState, _input: DoctorInput) -> CallToolResult {
+    match kebab_app::doctor_with_config_path(state.config_path.as_deref()) {
+        Ok(report) => match serde_json::to_string(&report) {
+            Ok(json) => to_tool_success(json),
+            Err(e) => to_tool_error(&anyhow::anyhow!(e)),
+        },
+        Err(e) => to_tool_error(&e),
+    }
+}

crates/kebab-mcp/src/tools/mod.rs

@@ -1,6 +1,6 @@
 //! Tool implementations — one module per tool.
 
 pub mod schema;
-// pub mod doctor;   // wired in Plan Task 5
+pub mod doctor;
 // pub mod search;   // wired in Plan Task 6
 // pub mod ask;      // wired in Plan Task 7