VS Code extension

The extension is ergonomics over the same core library the CLI uses, so the editor and CI can never disagree about what counts as stale.

• Reverse-index CodeLens: above any anchored symbol or region, "Referenced by N docs". Editing anchored code is the moment the author still has context; the lens puts the doc debt in view exactly then. Click peeks the referencing locations.
• Markdown diagnostics: stale and broken references get squiggles with the state and both hashes, and the squiggle's severity follows the project's gate level: strict shows drift as a warning and a broken ref as an error; lenient keeps the broken ref an error but softens drift to an information hint; advisory shows everything as a hint, since nothing gates. A quick fix on the squiggle jumps to the referenced code, opens the approved-vs-current drift diff for that one claim, or approves it, so you can compare and contrast without leaving the diagnostic.
• Drift diffs: Show Claim Drift opens one diff tab per stale claim (approved content recovered from git history versus current), and the Approve Claims flow opens the same diffs before its confirmation, so approval happens next to the evidence.
• Create anchor: select code, run "docref: create anchor". Inserts a marker pair (name prompted, comment leader auto-detected) or, when the selection is exactly a declaration, copies the symbol ref with no marker inserted.
• Reference autocomplete: typing a docref= or src= value in a markdown file completes the file path (within the project's [anchors] scope), then the symbol or @region inside it, and inserts the :sha already computed; nobody types a hash by hand. Multi-source claims complete the segment after each comma. Outside a reference value, the claim-block scaffold drops in the begin/end markers and parks the cursor on src=, where the same autocomplete takes over; a hand-written claim needs no markers typed by hand. Reach it via the Docref: Insert Claim Block command (palette or markdown right-click), or in the suggest list by typing the docref shorthand or pressing Ctrl+Space; markdown does not open suggestions on plain typing. When a referenced file has no anchorable symbols or markers, the list says so instead of sitting empty.
• Collection sidebar: add the current selection to a chosen collection file as a claim with an empty note; reorder and annotate; "fold into document" moves blocks into a target markdown file. All of it is plain-text editing of the collection file, so the sidebar is optional, and agents or humans can edit the same file directly.
• Status bar: repo-wide count of stale/broken references, updated on save of any anchored file (re-resolving only refs into the saved file keeps this instant); it names the active gate level when that level is not strict.