workflow: project-driven agent workflow (docs-first, TODO/ROADMAP tracking, verify-before-done)

- system prompt gains a Project workflow block when the repo tracks its own
  progress (TODO.md/ROADMAP.md/docs): read the task list first and keep it
  current, spec-first for non-trivial work, complete unit tests, verify before
  declaring done
- TODO.md + ROADMAP.md loaded as 'Project tracker' instruction blocks, capped
  tighter than AGENTS.md so the agent sees the shape without drowning in it
- one soft nudge per session when a turn writes files without touching the
  task list; suppressed when todo_write was called; never a gate
- /workflow command + panel showing TODO/ROADMAP/docs presence, line/file
  counts, nudge state
- config: workflow.enabled (default true), workflow.docsDir (default docs)
- prompt-cache version key extended with wf: so toggling the workflow busts
  the cached system prompt
- docs: docs/workflow.md, configuration table row, ROADMAP + TODO entries
- tests: test/workflow.test.ts (9 tests)

830 tests pass, typecheck clean, build green, live headless demo verified

src/commands.ts

@@ -31,6 +31,7 @@ export type CommandAction =
   | { type: 'changes' }
   | { type: 'search'; query: string }
   | { type: 'fork' }
+  | { type: 'workflow' }
   /** A custom command from a markdown file, expanded against its arguments. */
   | { type: 'custom'; command: CustomCommand; args: string[] }
   | { type: 'unknown'; name: string };
@@ -71,6 +72,7 @@ export const COMMANDS: CommandSpec[] = [
   { name: 'changes', summary: 'show what the last turn changed on disk' },
   { name: 'search', arg: '<query>', summary: 'search saved sessions for a phrase' },
   { name: 'fork', summary: 'fork the session at the last turn boundary (keeps the original)' },
+  { name: 'workflow', summary: 'show project workflow state: TODO/ROADMAP tracking, docs, nudges' },
   { name: 'clear', summary: 'clear the transcript and history' },
   { name: 'exit', aliases: ['quit'], summary: 'quit' },
 ];
@@ -245,6 +247,8 @@ export function parseCommand(raw: string, custom: readonly CustomCommand[] = [])
       return arg ? { type: 'search', query: arg } : { type: 'info', text: 'usage: /search <query>' };
     case 'fork':
       return { type: 'fork' };
+    case 'workflow':
+      return { type: 'workflow' };
     default: {
       const cmd = custom.find((c) => c.name === name);
       return cmd ? { type: 'custom', command: cmd, args: arg ? arg.split(/\s+/) : [] } : { type: 'unknown', name };