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-protocol/src/capabilities.rs

@@ -4,12 +4,9 @@ use std::collections::HashMap;
 
 use serde::{Deserialize, Serialize};
 
-/// Per-tool wire-traveling capabilities. Defaults conservatively (no
-/// progress, no cancel, single concurrency, no hooks).
 #[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
 pub struct ToolCapabilities {
-    /// Streaming declaration. `None` — the default for every tool today —
-    /// means the tool never emits partial-result progress.
+    /// `None` means the tool never emits partial-result progress.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub streaming: Option<StreamingSpec>,
 
@@ -17,8 +14,7 @@ pub struct ToolCapabilities {
     #[serde(default)]
     pub supports_cancel: bool,
 
-    /// Maximum concurrent invocations the tool will accept. `None` is
-    /// unlimited.
+    /// `None` is unlimited.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub max_concurrency: Option<u32>,
 
@@ -26,7 +22,6 @@ pub struct ToolCapabilities {
     #[serde(default)]
     pub is_read_only: bool,
 
-    /// Lifecycle hooks the tool opts in to receive.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub hooks: Vec<HookKind>,
 
@@ -43,17 +38,14 @@ pub struct ToolCapabilities {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub timeout_ms: Option<u64>,
 
-    /// Multi-agent write-coordination scope. Tools that mutate external
-    /// state must declare `Write` so the computer hub routes them to the
-    /// leader agent only. Absence is treated as `Read`.
+    /// Absence is treated as [`ToolScope::Read`].
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub tool_scope: Option<ToolScope>,
 }
 
-/// How a tool streams partial results. Declared once in
-/// [`ToolCapabilities::streaming`] and consumed at the source to stamp a
-/// self-describing progress envelope; downstream layers dispatch on that
-/// envelope rather than the tool's identity.
+/// How a tool streams partial results. The spec is stamped onto a
+/// self-describing progress envelope at the source, so downstream layers
+/// dispatch on the envelope rather than on the tool's identity.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct StreamingSpec {
     /// Stable snake_case discriminator the tool stamps on its
@@ -67,7 +59,6 @@ pub struct StreamingSpec {
     pub max_delta_bytes: Option<u32>,
 }
 
-/// Lifecycle hook a tool may opt in to receive.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub enum HookKind {
@@ -86,21 +77,19 @@ pub enum HookKind {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub enum ToolScope {
-    /// Tool does not mutate external state.
     Read,
-    /// Tool mutates external state.
     Write,
 }
 
-/// Per-tool notification schemas. Keys are the notification `kind` strings
-/// the computer hub validates against.
+/// Keys are the notification `kind` strings the computer hub validates
+/// against.
 #[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
 pub struct NotificationSchemas {
-    /// Schemas for notifications the tool emits to subscribers.
+    /// Notifications the tool emits to subscribers.
     #[serde(default, skip_serializing_if = "HashMap::is_empty")]
     pub outbound: HashMap<String, serde_json::Value>,
 
-    /// Schemas for notifications the harness sends to the tool.
+    /// Notifications the harness sends to the tool.
     #[serde(default, skip_serializing_if = "HashMap::is_empty")]
     pub inbound: HashMap<String, serde_json::Value>,
 }