Fix Discord component interaction dispatch

[pattyboy813]

Summary

Resolve Discord Components V2 channel-select partials through the interaction guild cache, falling back to Discord fetch only when absent. Validate the resolved channel is a standard text channel in the same guild before checking Bill's required permissions and persisting it.

Make the persistent profile button and select DynamicItem templates disjoint while preserving existing custom IDs. The supported-action registry ensures every emitted wizard action has exactly one dispatcher and prevents unknown actions from being generated.

Add focused regressions for real discord.py application-command partials, cache and fetch resolution, rejected channel kinds and guilds, fetch errors, persisted channel IDs, profile select/button dispatcher exclusivity, and action exhaustiveness.

Related work

None.

Checks

• Python compile, Ruff, and pytest pass (70 tests)
• Worker typecheck and Vitest pass (228 tests)
• No secrets, private IDs, or local environment files are included
• Documentation and manual steps are updated when needed (not applicable)

Risk and rollout

Low. Existing persistent custom IDs remain compatible. Authorization, stale-revision handling, permission validation, and persistence contracts are unchanged. No deployment or data changes are included.