feat(commands): deterministic [commands] reflex — drive skills without the LLM

[ceounittt]

What & why

A user with no LLM turn can't drive Albert at all. This PR adds deterministic /commands: a config-declared [commands] table binds a /name to a skill script, runs it via forkd, and renders the JSON output through a template — as a reflex, before and instead of the LLM. It's the deterministic counterpart to the owner-only ACL commands (/allow /deny /allowed). Fast, cheap, predictable: no model call, no agent turn.

Covers both code and config in a single PR.

How it works

[commands."/status"]
skill_path = "your-skill/scripts/run.py"   # relative to the skills dir (forkd skill_path)
args       = ["status"]                     # the script's subcommand + flags
reply      = "Status: {state} (uptime {uptime})."
help       = "service status"

[commands."/echo"]                            # /echo hello
skill_path   = "your-skill/scripts/run.py"
args         = ["echo", "{arg}"]              # a trailing {arg} takes the user's text
reply        = "You said: {text}"
owner_only   = true

• /name arg → forkd forkd.run {skill_path, interpreter, args, timeout_secs} → renders {field} / {nested.field} from the script's JSON stdout.
• A single trailing {arg} in args receives the text after the command word; calling it with no text returns a short usage hint (never a stray empty argv token).
• reply template: an unresolved path renders as —, non-JSON stdout is echoed as-is, and the reply is capped to Telegram's message limit.
• /help is auto-composed: the built-in help plus the listing of configured commands.

Security

• owner_only is enforced before any forkd dispatch (reuses acl::is_owner).
• forkd runs argv with no shell — argument injection is inert; {arg} is substituted only into args, never into skill_path/interpreter (both config-only).
• The command branch does not log the message text or output at INFO; no secret/PII leaks to the log.
• Load-time validation: command names must start with /; a collision with a built-in reflex is warned about.

Tests

19 unit tests over build_args / fill / resolve / render / capped / help_listing (edge cases: empty {arg}, unbalanced braces, a value containing {...} is not re-expanded, timeout vs non-zero exit, oversized-reply truncation). cargo test and cargo build --release are green.

Files

• src/commands.rs — the dispatcher (new); src/config.rs — CommandSpec + validation; src/cogitator.rs — reflex wiring + /help.
• albert.toml, README.md, docs/configuration.md, docs/structure.md — example + reference.