Comment and Documentation Cleanup

- Cap every inline `//` comment block at 3 lines; distil the rationale
  rather than delete it. Enforced by a new comment-guard CI check.
- Fix stale and orphaned rustdoc: broken intra-doc links (renamed or
  removed items), doc blocks that had merged onto the wrong item (leaving
  the intended item undocumented), and doc-contradicts-code drift.
- Add a doc-links CI check (cargo doc, deny broken intra-doc links) so
  both classes of comment rot are caught going forward.

.github/workflows/comment-guard.yml

@@ -0,0 +1,15 @@
+name: comment-guard
+
+# Fails if any inline `//` comment block runs longer than 3 lines. Rustdoc
+# (`///`, `//!`) is exempt. Keeps explanatory comments terse; long rationale
+# belongs in a doc comment or a design note, not an inline wall.
+
+on: [push, pull_request]
+
+jobs:
+  comment-guard:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+      - name: Run comment-guard
+        run: python3 ci/comment-guard.py

.github/workflows/doc-links.yml

@@ -0,0 +1,32 @@
+name: doc-links
+
+# Fails on broken intra-doc links in `///`/`//!` doc comments (e.g. a `[Type]`
+# link to a renamed/removed item). Catches doc drift that `cargo build` misses.
+#
+# libfreemkv path-deps ../freemkv-unlock on the branch tip, so — like ci.yml —
+# both repos are checked out into sibling subdirectories for the path dep to
+# resolve.
+
+on: [push, pull_request]
+
+jobs:
+  doc-links:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          path: libfreemkv
+      - uses: actions/checkout@v7
+        with:
+          repository: freemkv/freemkv-unlock
+          ref: "${{ github.ref_name == 'qa' && 'qa' || 'dev' }}"
+          path: freemkv-unlock
+      - uses: dtolnay/rust-toolchain@1.98.0
+      - uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: libfreemkv
+      - name: cargo doc (deny broken intra-doc links)
+        working-directory: libfreemkv
+        env:
+          RUSTDOCFLAGS: "-D rustdoc::broken_intra_doc_links"
+        run: cargo doc --no-deps --document-private-items --lib --bins