docs: comprehensive documentation audit — fix stale info, expand thin pages, add depth (#5393)

Major changes across 20 documentation pages:

Staleness fixes:
- Fix FAQ: wrong import path (hermes.agent → run_agent)
- Fix FAQ: stale Gemini 2.0 model → Gemini 3 Flash
- Fix integrations/index: missing MiniMax TTS provider
- Fix integrations/index: web_crawl is not a registered tool
- Fix sessions: add all 19 session sources (was only 5)
- Fix cron: add all 18 delivery targets (was only telegram/discord)
- Fix webhooks: add all delivery targets
- Fix overview: add missing MCP, memory providers, credential pools
- Fix all line-number references → use function name searches instead
- Update file size estimates (run_agent ~9200, gateway ~7200, cli ~8500)

Expanded thin pages (< 150 lines → substantial depth):
- honcho.md: 43 → 108 lines — added feature comparison, tools, config, CLI
- overview.md: 49 → 55 lines — added MCP, memory providers, credential pools
- toolsets-reference.md: 57 → 175 lines — added explanations, config examples,
  custom toolsets, wildcards, platform differences table
- optional-skills-catalog.md: 74 → 153 lines — added 25+ missing skills across
  communication, devops, mlops (18!), productivity, research categories
- integrations/index.md: 82 → 115 lines — added messaging, HA, plugins sections
- cron-internals.md: 90 → 195 lines — added job JSON example, lifecycle states,
  tick cycle, delivery targets, script-backed jobs, CLI interface
- gateway-internals.md: 111 → 250 lines — added architecture diagram, message
  flow, two-level guard, platform adapters, token locks, process management
- agent-loop.md: 112 → 235 lines — added entry points, API mode resolution,
  turn lifecycle detail, message alternation rules, tool execution flow,
  callback table, budget tracking, compression details
- architecture.md: 152 → 295 lines — added system overview diagram, data flow
  diagrams, design principles table, dependency chain

Other depth additions:
- context-references.md: added platform availability, compression interaction,
  common patterns sections
- slash-commands.md: added quick commands config example, alias resolution
- image-generation.md: added platform delivery table
- tools-reference.md: added tool counts, MCP tools note
- index.md: updated platform count (5 → 14+), tool count (40+ → 47)

website/docs/user-guide/messaging/webhooks.md

@@ -70,7 +70,7 @@ Routes define how different webhook sources are handled. Each route is a named e
 | `secret` | **Yes** | HMAC secret for signature validation. Falls back to the global `secret` if not set on the route. Set to `"INSECURE_NO_AUTH"` for testing only (skips validation). |
 | `prompt` | No | Template string with dot-notation payload access (e.g. `{pull_request.title}`). If omitted, the full JSON payload is dumped into the prompt. |
 | `skills` | No | List of skill names to load for the agent run. |
-| `deliver` | No | Where to send the response: `github_comment`, `telegram`, `discord`, `slack`, `signal`, `sms`, or `log` (default). |
+| `deliver` | No | Where to send the response: `github_comment`, `telegram`, `discord`, `slack`, `signal`, `matrix`, `mattermost`, `email`, `sms`, `dingtalk`, `feishu`, `wecom`, or `log` (default). |
 | `deliver_extra` | No | Additional delivery config — keys depend on `deliver` type (e.g. `repo`, `pr_number`, `chat_id`). Values support the same `{dot.notation}` templates as `prompt`. |
 
 ### Full example