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/cli.md

@@ -26,6 +26,7 @@ bunx oh-my-opencode
 | `run <message>` | Non-interactive OpenCode session runner with completion enforcement |
 | `get-local-version` | Show current installed version and check for updates |
 | `refresh-model-capabilities` | Refresh cached model capabilities snapshot from models.dev |
+| `boulder` | Inspect Sisyphus boulder work-state (active plan, per-task timers, session lineage) |
 | `version` | Show CLI version |
 | `mcp oauth` | OAuth token management for MCP servers |