docs: deep quality pass — expand 10 thin pages, fix specific issues (#4134)

Developer guide stubs expanded to full documentation:
- trajectory-format.md: 56→233 lines (JSONL format, ShareGPT example,
  normalization rules, reasoning markup, replay code)
- session-storage.md: 66→388 lines (SQLite schema, migration table,
  FTS5 search syntax, lineage queries, Python API examples)
- context-compression-and-caching.md: 72→321 lines (dual compression
  system, config defaults, 4-phase algorithm, before/after example,
  prompt caching mechanics, cache-aware patterns)
- tools-runtime.md: 65→246 lines (registry API, dispatch flow,
  availability checking, error wrapping, approval flow)
- prompt-assembly.md: 89→246 lines (concrete assembled prompt example,
  SOUL.md injection, context file discovery table)

User-facing pages expanded:
- docker.md: 62→224 lines (volumes, env forwarding, docker-compose,
  resource limits, troubleshooting)
- updating.md: 79→167 lines (update behavior, version checking,
  rollback instructions, Nix users)
- skins.md: 80→206 lines (all color/spinner/branding keys, built-in
  skin descriptions, full custom skin YAML template)

Hub pages improved:
- integrations/index.md: 25→82 lines (web search backends table,
  TTS/browser providers, quick config example)
- features/overview.md: added Integrations section with 6 missing links

Specific fixes:
- configuration.md: removed duplicate Gateway Streaming section
- mcp.md: removed internal "PR work" language
- plugins.md: added inline minimal plugin example (self-contained)

13 files changed, ~1700 lines added. Docusaurus build verified clean.

website/docs/user-guide/configuration.md

@@ -860,12 +860,15 @@ When enabled, responses appear token-by-token inside a streaming box. Tool calls
 ```yaml
 streaming:
   enabled: true           # Enable progressive message editing
+  transport: edit         # "edit" (progressive message editing) or "off"
   edit_interval: 0.3      # Seconds between message edits
   buffer_threshold: 40    # Characters before forcing an edit flush
   cursor: " ▉"            # Cursor shown during streaming
 ```
 
-When enabled, the bot sends a message on the first token, then progressively edits it as more tokens arrive. Platforms that don't support message editing (Signal, Email) gracefully skip streaming and deliver the final response normally.
+When enabled, the bot sends a message on the first token, then progressively edits it as more tokens arrive. Platforms that don't support message editing (Signal, Email, Home Assistant) are auto-detected on the first attempt — streaming is gracefully disabled for that session with no flood of messages.
+
+**Overflow handling:** If the streamed text exceeds the platform's message length limit (~4096 chars), the current message is finalized and a new one starts automatically.
 
 :::note
 Streaming is disabled by default. Enable it in `~/.hermes/config.yaml` to try the streaming UX.
@@ -929,23 +932,6 @@ Usage: type `/status`, `/disk`, `/update`, or `/gpu` in the CLI or any messaging
 - **Type** — only `exec` is supported (runs a shell command); other types show an error
 - **Works everywhere** — CLI, Telegram, Discord, Slack, WhatsApp, Signal, Email, Home Assistant
 
-## Gateway Streaming
-
-Enable progressive token delivery on messaging platforms. When streaming is enabled, responses appear character-by-character in Telegram, Discord, and Slack via message editing, rather than waiting for the full response.
-
-```yaml
-streaming:
-  enabled: false              # Enable streaming token delivery (default: off)
-  transport: edit             # "edit" (progressive message editing) or "off"
-  edit_interval: 0.3          # Min seconds between message edits
-  buffer_threshold: 40        # Characters accumulated before forcing an edit
-  cursor: " ▉"               # Cursor character shown during streaming
-```
-
-**Platform support:** Telegram, Discord, and Slack support edit-based streaming. Platforms that don't support message editing (Signal, Email, Home Assistant) are auto-detected on the first attempt — streaming is gracefully disabled for that session with no flood of messages.
-
-**Overflow handling:** If the streamed text exceeds the platform's message length limit (~4096 chars), the current message is finalized and a new one starts automatically.
-
 ## Human Delay
 
 Simulate human-like response pacing in messaging platforms: