feat(claudebox): pass mode=public to the v2 /run webhook (#23607)

Follow-up to #23600 (merged), which pointed CI at the ClaudeBox v2
`/run` webhook but did not pass a mode.

A v2 session's GitHub repo access is derived from its mode
(`slack_route.effective_mode` in session meta). The `slackbot` group's
repos are entirely mode-scoped, so a `/run` session **without** a mode
only resolves the group chain's unscoped repos (`claudebox` + `honk-ai`)
and **cannot write `aztec-packages`** — the same "no GitHub access"
failure #23600 set out to fix. Prompt text has no effect; `/run` never
parses mode flags.

This passes **`mode: "public"`** in both dispatch payloads (overridable
via repo var `CLAUDEBOX_MODE`), so kickoff/`/claudebox`/review sessions
resolve the public read-write repo set and can open PRs against
aztec-packages.

**Depends on AztecProtocol/claudebox#625**, which adds `mode` support to
the v2 `/run` endpoint (it stamps `effective_mode` into the new
session's meta). Without #625 deployed, `mode` is accepted but ignored,
so land/deploy #625 first or together.

## Testing
- `bash -n` on every `run:` body (7 steps) and YAML parse — pass.
- `jq` payload validated with `mode: "public"` for the issue-comment,
workflow_dispatch, and review shapes — valid JSON matching the v2
`RunRequest`.

---
*Created by
[claudebox](https://claudebox.work/v2/sessions/4b53f2dd8370a83a) ·
group: `slackbot`*

Author: ludamad

.github/workflows/claudebox.yml

@@ -129,6 +129,10 @@ jobs:
           AUTHOR: ${{ github.event.comment.user.login || github.actor }}
           SLACK_CHANNEL: ${{ inputs.slack_channel || '' }}
           SLACK_THREAD_TS: ${{ inputs.slack_thread_ts || '' }}
+          # Public mode grants the session read-write access to public repos
+          # (aztec-packages). Without it the session only gets the group's
+          # unscoped repos and cannot open PRs against aztec-packages.
+          CLAUDEBOX_MODE: ${{ vars.CLAUDEBOX_MODE || 'public' }}
         run: |
           if [ -z "${CLAUDEBOX_API_SECRET:-}" ]; then
             echo "ERROR: CLAUDEBOX_API_SECRET is not set; cannot dispatch ClaudeBox v2"
@@ -145,7 +149,8 @@ jobs:
             --arg link "$CLAUDEBOX_LINK" \
             --arg slack_channel "$SLACK_CHANNEL" \
             --arg slack_thread_ts "$SLACK_THREAD_TS" \
-            '{prompt: $prompt, user: $user, repo: $repo, run_url: $run_url, link: $link, slack_channel: $slack_channel, slack_thread_ts: $slack_thread_ts}
+            --arg mode "$CLAUDEBOX_MODE" \
+            '{prompt: $prompt, user: $user, repo: $repo, run_url: $run_url, link: $link, slack_channel: $slack_channel, slack_thread_ts: $slack_thread_ts, mode: $mode}
              + (if $comment_id != "" then {comment_id: ($comment_id | tonumber)} else {} end)
              + (if $run_comment_id != "" then {run_comment_id: ($run_comment_id | tonumber)} else {} end)')
 
@@ -203,6 +208,7 @@ jobs:
           RUN_COMMENT_ID: ${{ steps.status_comment.outputs.run_comment_id || '' }}
           RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
           REPO: ${{ github.repository }}
+          CLAUDEBOX_MODE: ${{ vars.CLAUDEBOX_MODE || 'public' }}
         run: |
           if [ -z "${CLAUDEBOX_API_SECRET:-}" ]; then
             echo "ERROR: CLAUDEBOX_API_SECRET is not set; cannot dispatch ClaudeBox v2"
@@ -226,7 +232,8 @@ jobs:
             --arg repo "$REPO" \
             --arg run_url "$RUN_URL" \
             --arg link "$PR_URL" \
-            '{prompt: $prompt, user: $user, repo: $repo, run_url: $run_url, link: $link}
+            --arg mode "$CLAUDEBOX_MODE" \
+            '{prompt: $prompt, user: $user, repo: $repo, run_url: $run_url, link: $link, mode: $mode}
              + (if $run_comment_id != "" then {run_comment_id: ($run_comment_id | tonumber)} else {} end)')
 
           RESPONSE=$(curl -sS -w "\n%{http_code}" \