docs(cron): add cron user guide + Claude speedrun protocol

- docs/cron-guide.md: comprehensive user/operator guide for the Cron
  feature (fields, schedule types, prompt security, execution flow, API,
  SSE, limits, troubleshooting), sourced from the implementation.
- SPEEDRUN.md: fast-execution protocol for Claude grounded in this repo's
  real commands and CLAUDE.md guardrails.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SSVnYek4nq4Ztmbb3SrCA5

SPEEDRUN.md

@@ -0,0 +1,104 @@
+# SPEEDRUN.md — Fast-execution protocol for Claude
+
+Read this when the goal is **throughput**: get correct, verified work done with
+minimum ceremony. This does **not** relax correctness or the safety rules in
+`CLAUDE.md` — those still win. It removes _waste_, not _rigor_.
+
+> Precedence: `CLAUDE.md` > explicit user instructions > this file. If anything
+> here conflicts with `CLAUDE.md`, `CLAUDE.md` wins.
+
+---
+
+## The mindset
+
+- **Act, don't announce.** No "I'm going to now…" preamble. Do the thing, report
+  the result.
+- **Cheapest proof that the change works.** Pick the smallest check that actually
+  demonstrates correctness — not the biggest.
+- **Batch aggressively.** Independent reads, greps, and edits go in **one**
+  message with parallel tool calls. Never serialize work that has no dependency.
+- **Momentum over perfection.** Land a correct increment, verify it, move on.
+  Don't gold-plate untouched code.
+
+---
+
+## Loop (repeat until done)
+
+1. **Orient once** — one parallel burst of reads/greps to load the context you
+   need. Don't re-read files the harness says are already current.
+2. **Change** — make the edit(s). Batch independent edits.
+3. **Verify cheaply** — the smallest check that proves _this_ change (see below).
+4. **Advance** — next item. Only re-verify what you touched.
+5. **Stop** at: list empty, a hard blocker, or a decision that's genuinely the
+   user's to make.
+
+---
+
+## Verification ladder — climb only as high as the change needs
+
+| Change kind | Cheapest sufficient check |
+|-------------|---------------------------|
+| Types / signatures / imports | `tsc --noEmit` (or `--watch` already running) |
+| One module's logic | `npm test -- test/<file>.test.ts` (the **one** relevant file) |
+| A named behavior | `npm test -- -t "pattern"` |
+| Route/handler | `app.inject()` route test, or one `curl` against the running dev server |
+| Frontend render | Playwright load + assert (`waitUntil: 'domcontentloaded'`, wait 3–4s) |
+| Broad / pre-merge | `npm run test:ci` (the CI-equivalent sweep) |
+
+**Hard rules (never skip, even in a rush):**
+- ⚠️ **Never run bare `npm test`** — it pulls in browser/visual suites that hang
+  or fail locally. Always pass a file or `-t`, or use `test:ci`.
+- ⚠️ **Never COM without verifying the change actually works** first (curl the
+  endpoint / Playwright the UI). "Compiles" ≠ "works".
+- ⚠️ **Session safety** — check `$CODEMAN_MUX`; never `tmux kill-session` /
+  `pkill claude` in a managed session.
+- ⚠️ **Single-line prompts** for any programmatic session input.
+
+---
+
+## Speed tactics that pay off here
+
+- **Parallel exploration**: dispatch `Explore` subagents (or one parallel grep
+  burst) instead of serial file-by-file reading when scope is uncertain.
+- **`tsc --noEmit --watch`** in the background — instant type feedback, no repeat
+  cold starts.
+- **Target one test file** — `fileParallelism: false` means the suite is serial;
+  running one file is dramatically faster than the sweep.
+- **`curl localhost:3000/api/...`** beats spinning up a browser for backend
+  checks. Reserve Playwright for actual UI rendering.
+- **Trust the harness** — if it says a file you just edited is current, don't
+  re-Read it to "confirm". The Edit already succeeded or it would have errored.
+
+---
+
+## Anti-patterns (these masquerade as speed, but cost time)
+
+- Running the full test suite to check a one-file change.
+- Re-reading files you already have in context.
+- Narrating a plan you're about to execute anyway.
+- Serial tool calls that have no dependency between them.
+- Claiming "done / fixed / passing" **before** running the check that proves it.
+- Deploying (COM) on green typecheck alone, without exercising the real flow.
+
+---
+
+## Stop-conditions (don't rush past these)
+
+Stop and surface, don't guess, when you hit:
+- A **destructive / hard-to-reverse** action (delete, overwrite, force-push).
+- An **outward-facing** action (publishing, sending, deploying) not already
+  authorized.
+- A **genuine product decision** the code can't answer.
+- A **failing verification you can't explain** — debug it (see
+  `superpowers:systematic-debugging`), don't paper over it.
+
+---
+
+## Definition of done
+
+A task is done when **all** hold:
+- The change is made.
+- The cheapest sufficient check **ran** and **passed** — evidence, not assertion.
+- No new type errors / lint errors introduced (`tsc --noEmit`, `npm run lint`).
+- You state plainly what was done and what proved it. If a step was skipped or a
+  test failed, say so — don't hedge, don't overclaim.