feat: built-in "kata" hook type (mirror existing "beads" hook)

[Joi]

Summary

roborev ships a built-in [[hooks]] type = "beads" that emits a bd create on review events, automatically filing review findings as beads issues. Ask: ship an analogous type = "kata" that emits kata create against the workspace's kata project.

Current state

internal/daemon/hooks.go currently special-cases only "beads":

if hook.Type == "beads" {
    return beadsCommand(event)
}

There is no equivalent for kata. Users who've migrated to kata as their primary tracker today have to either:

• write a command-type hook with a hand-rolled kata create shell, or
• install a sidecar like bogorad/roborev-to-beads and live with the beads → kata indirection.

Neither is great when kata and roborev are by the same author and could integrate natively.

Proposed shape

In a repo's .roborev.toml:

[[hooks]]
type = "kata"
events = ["review.failed", "review.completed"]   # whatever beads supports
# optional:
project = "<name>"          # defaults to the workspace's .kata.toml binding
labels = ["roborev", "from-review"]
priority = 2

The kata equivalent of beadsCommand(event) would call something like:

kata create "<finding title>" \
  --project <project> \
  --body-file <(<finding markdown>) \
  --label roborev --label severity:<level> \
  --idempotency-key "roborev:<job-id>:<finding-id>" \
  --agent

The two load-bearing flags for an unattended emitter:

• --idempotency-key — matches the existing beads-hook dedup intent and is safe against daemon retries. The daemon returns the existing issue instead of creating a duplicate.
• --agent (the new --format agent from kata PR Add roborev skills for Claude Code and Codex, add roborev skills install command #55) — single-token OK <verb> lines, cheap to log and parse.

Small bonus

internal/git/git.go already excludes **/.beads/** from review diffs. The kata equivalents would be .kata.toml and .kata.local.toml — binding/config files, not code-review material.

Context

Same author owns both projects, so built-in support feels like the right home rather than living as a third-party sidecar. Happy to draft a PR if there's interest.