Remove stale phase/spec references from code comments

Strip "Phase N", "SPEC §X.Y", and "v1.x" planning labels from comments
across the Rust crates and editor layers now that those tracking
artifacts are gone. Comments only — no logic, strings, or test names
touched.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

crates/nuwiki-lsp/src/export.rs

@@ -1,4 +1,4 @@
-//! HTML export — pure helpers shared by the Phase 17 `nuwiki.export.*`
+//! HTML export — pure helpers shared by the `nuwiki.export.*`
 //! command handlers. Side-effecting work (reading the template from
 //! disk, writing the rendered HTML, copying CSS) lives in `commands.rs`
 //! since the dispatcher is the one with a `&Backend` and async context.