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/codegen/kigi-sandbox/src/profiles.rs

@@ -367,10 +367,11 @@ impl ProfileName {
                     "/run",
                     // NSS/SSSD (and similar) under /var — needed beyond resolv.conf alone
                     "/var",
-                    // macOS-specific paths (filtered by exists() below)
-                    "/System",  // Security framework, dylibs, TLS certificates
-                    "/Library", // System-wide frameworks
-                    "/private", // Real path behind /etc, /tmp, /var symlinks
+                    // macOS-specific paths, filtered by exists() below:
+                    // /System (security framework, dylibs, TLS certs),
+                    // /Library (system-wide frameworks), /private (real path
+                    // behind the /etc, /tmp, /var symlinks).
+                    "/System", "/Library", "/private",
                 ]
                 .iter()
                 .map(PathBuf::from)