docs: comprehensive docs audit — fix 12 stale/missing items across 10 pages (#3618)

Fixes found by auditing docs against recent PRs/commits:

Critical (misleading):
- hooks.md: Remove stale 'planned — not yet wired' markers for 4 hooks
  that are now active (#3542). Add correct callback signatures.
- security.md: Update tirith verdict behavior — block verdicts now go
  through approval flow instead of hard-blocking (#3428). Add pkill/killall
  self-termination guard and gateway-run backgrounding patterns (#3593).

New feature docs:
- configuration.md: Add tool_use_enforcement section with value table
  (auto/true/false/list) from #3551/#3528.
- configuration.md: Expand auxiliary config with per-task timeouts
  (compression 120s, web_extract 30s, approval 30s) from #3597.
- api-server.md: Add /v1/health alias, Security Headers section,
  CORS details (Max-Age, SSE headers, Idempotency-Key) from
  #3572/#3573/#3576/#3580/#3530.

Stale/incomplete:
- configuration.md: Fix Alibaba model name qwen-plus -> qwen3.5-plus (#3484).
- environment-variables.md: Specify actual DashScope default URL.
- cli-commands.md: Add alibaba to --provider list.
- fallback-providers.md: Add Alibaba/DashScope to provider table.
- email.md: Document noreply/automated sender filtering (#3606).
- toolsets-reference.md: Add 4 missing platform toolsets — matrix,
  mattermost, dingtalk, api-server (#3583).
- skills.md: List default GitHub taps including garrytan/gstack (#3605).

website/docs/reference/cli-commands.md

@@ -67,7 +67,7 @@ Common options:
 | `-q`, `--query "..."` | One-shot, non-interactive prompt. |
 | `-m`, `--model <model>` | Override the model for this run. |
 | `-t`, `--toolsets <csv>` | Enable a comma-separated set of toolsets. |
-| `--provider <provider>` | Force a provider: `auto`, `openrouter`, `nous`, `openai-codex`, `copilot`, `copilot-acp`, `anthropic`, `huggingface`, `zai`, `kimi-coding`, `minimax`, `minimax-cn`, `kilocode`. |
+| `--provider <provider>` | Force a provider: `auto`, `openrouter`, `nous`, `openai-codex`, `copilot`, `copilot-acp`, `anthropic`, `huggingface`, `alibaba`, `zai`, `kimi-coding`, `minimax`, `minimax-cn`, `kilocode`. |
 | `-s`, `--skills <name>` | Preload one or more skills for the session (can be repeated or comma-separated). |
 | `-v`, `--verbose` | Verbose output. |
 | `-Q`, `--quiet` | Programmatic mode: suppress banner/spinner/tool previews. |