Plugin init and config hook can block the opencode layer indefinitely

Title:
Plugin init and config hook can block the opencode layer indefinitely

Description:
packages/opencode/src/plugin/index.ts loads each internal plugin with await plugin(input)
and notifies each loaded hook with (hook as any).config?.(cfg). Neither call has a timeout
or any per-plugin log line about which plugin is currently being awaited. When a plugin
returns a promise that never resolves (sync throw inside a never-resolving promise, broken
native binding, etc.) the entire plugin layer init blocks until the process is killed; the
existing logError only fires on rejection, not on hang.

The npm-install-related hang from #33905 was fixed in #33905 itself. The two call sites in
plugin/index.ts still have no timeout and are unrelated to that fix.

Plugins: n/a
OpenCode version: dev (dc4449df0d)

Steps to reproduce:

1. Add a plugin to the internal plugins list whose plugin(input) returns a never-resolving
   Promise (or whose config hook does the same).
2. Start opencode against any project directory.
3. Plugin layer init never returns. No log line identifies which plugin is stuck.

Expected behaviour:

• The offending call fails or times out within a few seconds.
• The layer continues with the remaining plugins.
• The log identifies the plugin by name (or by index) so the misbehaving one is locatable.

Actual behaviour:

• The layer init blocks indefinitely.
• No log line is emitted until the process is killed externally.

Operating System: n/a (reproducible on any platform)
Terminal: n/a

Related / duplicate check:

• #33905 (closed): same symptom, but for the npm install inside the config layer; that path
  is already fixed.
• #38723: broader opencode run hangs during init; this issue is scoped to the plugin-layer
  init and config-hook call sites specifically.
• #37060: TUI port-related hang; different layer.