📝 Add backlog.tasks template and format rules

Introduce backlog.tasks, a project backlog in vscode-todotasks format
(not Markdown), seeded as a reusable template: Setup, v1.0, Bugs,
Enhancements, Documentation and Maintenance projects, with the
implementation tasks to be filled in later.

Document the format in AGENTS.md so agents can read and update the file,
recommend sandy081.todotasks in .vscode/extensions.json, and whitelist
"todotasks" for cspell, which both new mentions otherwise fail.

The branch, review and release policy is deliberately not asserted here:
it is unsettled, so it is tracked as a task-group under Setup and AGENTS.md
tells agents to take branch and merge instructions from the user until that
work is documented.

backlog.tasks

@@ -0,0 +1,44 @@
+Tasks
+
+Backlog and tracking for tiny-pattern-ts. Managed in vscode-todotasks format.
+
+---
+
+Setup:
+☐ Add gitea actions, blocked by missing runner => pi --session 01a06e72-e61e-7327-b3e9-3e11749a523f @high
+☐ Add gitea release page in CI @high
+☐ Split off template into separate package => pi --session 01a07dde-7050-7054-bb36-1606d7eb2bc3 @high
+☐ Document branching model @critical
+    ☐ Describe branching model: when to branch, base branch, naming
+    ☐ Clarify release workflow: who pushes `main`, CI as post-merge gate, drop PR usage
+
+v1.0:
+☐ API surface is stable and fully typed
+    ☐ Finalize public exports in `src/index.ts`
+    ☐ Document all exported types and functions
+    ☐ Add JSDoc for public APIs
+☐ Test coverage meets threshold
+    ☐ Achieve 100% branch coverage on `src/pattern.ts`
+    ☐ Achieve 100% branch coverage on `src/match.ts`
+    ☐ Achieve 100% branch coverage on `src/index.ts`
+☐ `dist/` output is clean
+    ☐ Verify `.d.ts` declarations match public exports
+    ☐ Ensure `.js` files use `.js` extensions (not `.ts`)
+    ☐ Test `attw --profile esm-only` passes
+
+Bugs:
+
+Enhancements:
+
+Documentation:
+☐ Add usage examples to README.md
+☐ Create `examples/` directory with runnable snippets
+☐ Add comparison section vs. other TS pattern-matching libs
+☐ Write migration guide for users coming from discriminated unions
+☐ Create backlog tasks for implementation
+
+Maintenance:
+✔ Set up lefthook pre-commit hook @done (9/8/2026, 10:52:56 AM)
+✔ Configure tsconfig strictest + node26 profiles @done (9/8/2026, 10:08:37 AM)
+✔ Add check:tsc as first tier in `npm run check` @done (9/8/2026, 10:08:37 AM)
+✔ Pin Node.js >= 26 via `.node-version` @done (9/8/2026, 10:08:38 AM)