Centralize encrypted bot profiles (#14)

Centralize ordered bot profiles and encrypted credentials in `bot-agents`.

- Exposes one action input: `master-key`.
- Uses Gitea’s automatic job token internally; dependent repositories provide no author/reviewer/profile inputs.
- Keeps encrypted Claude and reviewer credentials in `profiles.yml`; tokenless Codex uses its persisted subscription login.
- Falls back only on recognized quota exhaustion, with a distinct UID/home per profile and descendant cleanup before fallback.
- Separates decryption, agent execution, and reviewer posting so privileged credentials never enter an agent process.
- Installs `obra/superpowers` with the standard Skills CLI; removes custom discovery code.
- Adds root-level isolation, rollback, symlink, fallback, posting, YAML, and self-workflow CI coverage.

Checks: formatting, lint, all entrypoint type checks, 35 tests as root, diff check, secret scan, and repository diagnostics.
Reviewed-on: #14
Co-authored-by: Danny Kim <temeddix@gmail.com>
Co-committed-by: Danny Kim <temeddix@gmail.com>

profiles.yml

@@ -0,0 +1,7 @@
+reviewer-token: v1:XFUvCI9PnXVaW-ig:_3S9BvXywUp29cVYGA_EzFScKwC5oHkV9x2Ld8k-V_uiG7iA8n3fmjXCArzh2Lz-JDgy3IMTHoY
+profiles:
+  - type: claude
+    model: claude-sonnet-5
+    token: v1:-dyfF6ZicEhjPk4C:WCuMaGd09tYjtzUCl7abloRzPITvP5C35WpR372w3O_tcaD-ls-yV5sJBdU8iIVApZVCC98sY2gOyM3o9RMa8ciJq8Fuys7KxlYOp8QiluL9AYMSQi6rEsSH71EPWnxSACgo3uDQY8bWQpUlEZvXH9O-ZN9A58dh6b3vRg
+  - type: codex
+    model: gpt-5.6-terra