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/tests/commands_coverage.rs

@@ -1,6 +1,6 @@
 //! Command-coverage suite: at least one behavioural test for every
-//! documented `:Nuwiki*` / `:Vimwiki*` command (see `doc/nuwiki.txt`
-//! §5 COMMANDS).
+//! documented `:Nuwiki*` / `:Vimwiki*` command (see the COMMANDS section
+//! of `doc/nuwiki.txt`).
 //!
 //! The user-facing commands funnel through `workspace/executeCommand`
 //! into the Backend dispatcher, or — for follow/backlinks/rename — through