docs(comments): rewrite comments across all crates to the guidelines

Sweep every first-party crate source (1956 .rs files) to the project comment
guidelines: delete redundant restatements, decorative banners, change
narration, and end-of-line comments; keep and tighten the crucial ones
(invariants, bug rationale, SAFETY blocks, ported-source attribution).

No functional code changed. Every edit is proven comment-only against the
prior tree by a comment-stripping lexer (string/char/raw-string aware) plus a
separate doctest-fence check. Where removing a comment made rustfmt or clippy
want to re-lay-out adjacent code, the minimal triggering comment is restored so
code tokens stay byte-identical.

Gates green: cargo fmt --all --check (0 diffs), cargo check and cargo clippy
--workspace --all-targets (0 warnings).

Adds scripts/check_codegen_comment_guidelines.py — the enforcement gate for
these guidelines (flags banners, end-of-line comments, change narration, and
commented-out code).

crates/common/kigi-tool-runtime/src/search.rs

@@ -1,8 +1,8 @@
 //! Backend-agnostic tool search interface.
 //!
-//! `ToolSearchIndex` is a `Send + Sync` trait so concrete implementations
-//! can live in different crates (BM25, OpenSearch, in-memory linear) and
-//! be stored as `Arc<dyn ToolSearchIndex>` for shared access across tasks.
+//! `ToolSearchIndex` is `Send + Sync` so concrete implementations can live
+//! in different crates (BM25, OpenSearch, in-memory linear) and be stored
+//! as `Arc<dyn ToolSearchIndex>` for shared access across tasks.
 
 use std::sync::Arc;
 
@@ -13,26 +13,25 @@ pub struct ToolSearchResult {
     pub tool_name: String,
     /// Origin server name (e.g. `"linear"`).
     pub server_name: String,
-    /// Tool description.
     pub description: String,
     /// Backend-defined relevance score; comparable within a single
     /// snapshot but not across snapshots.
     pub score: f32,
     /// Parameter names from the tool's input schema, in declaration order.
     pub parameters: Vec<String>,
-    /// Full JSON Schema for the tool's input. Included so callers can
-    /// construct dispatched tool calls without a separate schema fetch.
+    /// Full JSON Schema for the tool's input so callers can construct
+    /// dispatched tool calls without a separate schema fetch.
     pub input_schema: serde_json::Value,
 }
 
-/// Snapshot of a search query — results plus index metadata captured from
-/// the same point-in-time view.
+/// Snapshot of a search query — results plus index metadata from the same
+/// point-in-time view.
 #[derive(Debug, Clone, PartialEq)]
 pub struct SearchSnapshot {
     pub results: Vec<ToolSearchResult>,
     /// Number of indexed tools that did not appear in `results`.
     pub total_hidden_tools: usize,
-    /// `true` when the index reflects all available tools. `false` while
+    /// `true` when the index reflects all available tools; `false` while
     /// the index source is still warming up.
     pub is_ready: bool,
 }
@@ -44,13 +43,11 @@ pub struct ServerSummary {
     pub name: String,
     /// Optional short description of the server's surface area.
     pub description: Option<String>,
-    /// Unqualified tool names, sorted alphabetically. Use
-    /// [`Self::tool_count`] for a count without indirection.
+    /// Unqualified tool names, sorted alphabetically.
     pub tool_names: Vec<String>,
 }
 
 impl ServerSummary {
-    /// Number of tools the server exposes.
     pub fn tool_count(&self) -> usize {
         self.tool_names.len()
     }
@@ -61,18 +58,16 @@ impl ServerSummary {
 /// Implementations must be `Send + Sync` so they can be wrapped in
 /// `Arc<dyn ToolSearchIndex>` and shared across concurrent tasks.
 pub trait ToolSearchIndex: Send + Sync {
-    /// Run a query against a single consistent index snapshot. Returning
-    /// the metadata alongside the results lets the caller render an
-    /// accurate "N results out of M" line without a second call.
+    /// Query a single consistent index snapshot. Metadata rides with the
+    /// results so the caller can render "N of M" without a second call.
     fn search_snapshot(&self, query: &str, limit: usize) -> SearchSnapshot;
 
-    /// Enumerate the unique servers in the index. Used to render the
-    /// system-reminder listing connected integrations.
+    /// Unique servers in the index (e.g. for a system-reminder listing
+    /// connected integrations).
     fn list_server_summaries(&self) -> Vec<ServerSummary>;
 }
 
-/// Resource wrapper for storing a `ToolSearchIndex` behind an `Arc` in
-/// shared resource maps.
+/// `ToolSearchIndex` behind an `Arc` for shared resource maps.
 #[derive(Clone)]
 pub struct ToolIndex(pub Arc<dyn ToolSearchIndex>);