docs: comprehensive docs audit — cover 13 features from last week's PRs (#5815)

Cover documentation gaps found by auditing all 50+ merged PRs from the past week:

tools-reference.md:
- Fix stale tool count (47→46, 11→10 browser tools) after browser_close removal
- Document notify_on_complete parameter in terminal tool description

telegram.md:
- Add Interactive Model Picker section (inline keyboard, provider/model drill-down)

discord.md:
- Add Interactive Model Picker section (Select dropdowns, 120s timeout)
- Add Native Slash Commands for Skills section (auto-registration at startup)

signal.md:
- Expand Attachments section with outgoing media delivery (send_image_file,
  send_voice, send_video, send_document via MEDIA: tags)

webhooks.md:
- Document {__raw__} special template token for full payload access
- Document Forum Topic Delivery via message_thread_id in deliver_extra

slack.md:
- Fix stale/misleading thread reply docs — thread replies no longer require
  @mention when bot has active session (3 locations updated)

security.md:
- Add cross-session isolation (layer 6) and input sanitization (layer 7)
  to security layers overview

feishu.md:
- Add WebSocket Tuning section (ws_reconnect_interval, ws_ping_interval)
- Add Per-Group Access Control section (group_rules with 5 policy types)

credential-pools.md:
- Add Delegation & Subagent Sharing section

delegation.md:
- Update key properties to mention credential pool inheritance

providers.md:
- Add Z.AI Endpoint Auto-Detection note
- Add xAI (Grok) Prompt Caching section

skills-catalog.md:
- Add p5js to creative skills category

website/docs/reference/tools-reference.md

@@ -6,9 +6,9 @@ description: "Authoritative reference for Hermes built-in tools, grouped by tool
 
 # Built-in Tools Reference
 
-This page documents all 48 built-in tools in the Hermes tool registry, grouped by toolset. Availability varies by platform, credentials, and enabled toolsets.
+This page documents all 47 built-in tools in the Hermes tool registry, grouped by toolset. Availability varies by platform, credentials, and enabled toolsets.
 
-**Quick counts:** 11 browser tools, 4 file tools, 10 RL tools, 4 Home Assistant tools, 2 terminal tools, 2 web tools, and 15 standalone tools across other toolsets.
+**Quick counts:** 10 browser tools, 4 file tools, 10 RL tools, 4 Home Assistant tools, 2 terminal tools, 2 web tools, and 15 standalone tools across other toolsets.
 
 :::tip MCP Tools
 In addition to built-in tools, Hermes can load tools dynamically from MCP servers. MCP tools appear with a server-name prefix (e.g., `github_create_issue` for the `github` MCP server). See [MCP Integration](/docs/user-guide/features/mcp) for configuration.
@@ -133,7 +133,7 @@ In addition to built-in tools, Hermes can load tools dynamically from MCP server
 | Tool | Description | Requires environment |
 |------|-------------|----------------------|
 | `process` | Manage background processes started with terminal(background=true). Actions: 'list' (show all), 'poll' (check status + new output), 'log' (full output with pagination), 'wait' (block until done or timeout), 'kill' (terminate), 'write' (sen… | — |
-| `terminal` | Execute shell commands on a Linux environment. Filesystem persists between calls. Do NOT use cat/head/tail to read files — use read_file instead. Do NOT use grep/rg/find to search — use search_files instead. Do NOT use ls to list directori… | — |
+| `terminal` | Execute shell commands on a Linux environment. Filesystem persists between calls. Set `background=true` for long-running servers. Set `notify_on_complete=true` (with `background=true`) to get an automatic notification when the process finishes — no polling needed. Do NOT use cat/head/tail — use read_file. Do NOT use grep/rg/find — use search_files. | — |
 
 ## `todo` toolset