docs: complete v4.1.1 drift sweep in reference and guide docs

Follow-up pass to catch drift my earlier docs commit missed:

docs/reference/features.md:
- 'Architecture Snapshot': 5-tier hook composition '52 base / 59 with team mode'
  to '54 base / 61 with team mode' (matches actual ToolGuard +2 from
  fsync-skip-warning + bash-file-read-guard).

docs/reference/cli.md:
- Add 'boulder' subcommand to Commands table (inspects boulder work-state).

docs/reference/configuration.md:
- Code comment example 'Kimi K2.5 work best' to 'Kimi K2.6 work best' to match
  current primary Sisyphus fallback chain.

docs/guide/installation.md:
- Add 'Kimi K2.6 (opencode-go, vercel)' row to the provider availability table
  above the existing K2.5 row.
- Selection priority footnote and 'Safe Overrides' chains updated to mention
  K2.6 alongside K2.5 in Sisyphus and Atlas chains.

docs/guide/agent-model-matching.md:
- Provider table 'Kimi K2.5' row to 'Kimi K2.6 / K2.5'.
- Atlas fallback chain mentions K2.6 instead of K2.5 alone.

docs/reference/configuration.md

@@ -77,7 +77,7 @@ Here's a practical starting configuration:
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
 
   "agents": {
-    // Main orchestrator: Claude Opus or Kimi K2.5 work best
+    // Main orchestrator: Claude Opus or Kimi K2.6 work best
     "sisyphus": {
       "model": "kimi-for-coding/k2p5",
       "ultrawork": { "model": "anthropic/claude-opus-4-7", "variant": "max" },