feat: Claude Code Monitor — lanes, pipelines and a merged workspace

Internal SmartGift build of a Claude Code monitoring dashboard.

Lanes: a durable unit of parallel agent work, one per working directory,
tracked across session restarts. Managed lanes are git worktrees the
dashboard provisions and can reset or remove behind a three-check destroy
guard and a counted preflight; adopted lanes are directories you already
own and are never destroyable.

Pipelines: a lane moves through pipeline stages. A stage the agent declares
with evidence renders green; a stage inferred from the tool-event stream
renders dashed amber and never counts as done. Detection is forward-only
within a 30-minute window, and never writes the declared stage.

Workspace: one page at /run with a lane grid, the selected lane's pipeline,
and a full Claude console behind a disclosure.

.claude/rules/file-headers.md

@@ -0,0 +1,6 @@
+# File Header Rules (binding for every coding agent)
+
+- Every applicable source file (`.js/.ts/.tsx/.cjs/.mjs/.py/.sh/.css` — excluding `node_modules/`, `dist/`, `data/`, minified/vendored, snapshots) MUST start with the header comment: a truthful file overview plus the exact line `@author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>`.
+- Creating a new applicable file → write the header before any code (after the shebang in scripts).
+- Editing a file that lacks the header → add it in the same change; if the edit changes the file's purpose, update the overview.
+- Formats and the repo-wide audit script live in `.claude/skills/file-headers/` (`bash .claude/skills/file-headers/scripts/check-headers.sh` must exit 0).