Add reference links: chezmoi, age, duckdb, launchd, age-spec, task-durations companion repo

AGENTS.md

@@ -3,6 +3,19 @@
 > **For Claude Code, Codex, Aider, or any other coding agent dropped into this repo.**
 > Follow this file top-to-bottom. It walks the user through replacing every placeholder with real values. Treat each numbered section as one Q&A round: ask the listed questions, wait for answers, fill in the files, then move on.
 
+## Background reading you may need mid-flow
+
+If you hit a chezmoi-specific question you can't answer from this file alone, consult the live docs:
+
+- **[chezmoi homepage](https://www.chezmoi.io)** — overview, install, quick start.
+- **[chezmoi command reference](https://www.chezmoi.io/reference/commands/)** — every subcommand (`init`, `add`, `apply`, `diff`, `update`, `re-add`, `edit-config`, `cd`, `source-path`, `execute-template`).
+- **[chezmoi templates](https://www.chezmoi.io/reference/templates/)** — the `{{ .chezmoi.homeDir }}` and `{{ .chezmoi.hostname }}` syntax used throughout this template.
+- **[chezmoi encryption](https://www.chezmoi.io/user-guide/encryption/age/)** — how `chezmoi add --encrypt` works with age.
+- **[age homepage](https://github.com/FiloSottile/age)** — keypair format, `age-keygen`, `age` and `age -d` commands.
+- **[Apple launchd guide](https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPSystemStartup/Chapters/CreatingLaunchdJobs.html)** — if a plist fails to load, this is the reference for `launchctl load`/`unload`/`list`.
+
+If the user asks about cross-fleet time estimates, the companion repo is [`task-durations`](https://gitea.tojo.team/cardinale/task-durations) (separate; install instructions in this template's README).
+
 ## Operating rules for this setup session
 
 1. **One question at a time.** Don't fire all questions in a giant wall of text. Ask one, wait for the answer, ask the next.