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/features/overview.md

@@ -33,6 +33,15 @@ Hermes Agent includes a rich set of capabilities that extend far beyond basic ch
 - **[Image Generation](image-generation.md)** — Generate images from text prompts using FAL.ai's FLUX 2 Pro model with automatic 2x upscaling via the Clarity Upscaler.
 - **[Voice & TTS](tts.md)** — Text-to-speech output and voice message transcription across all messaging platforms, with four provider options: Edge TTS (free), ElevenLabs, OpenAI TTS, and NeuTTS.
 
+## Integrations
+
+- **[Provider Routing](provider-routing.md)** — Fine-grained control over which AI providers handle your requests. Optimize for cost, speed, or quality with sorting, whitelists, blacklists, and priority ordering.
+- **[Fallback Providers](fallback-providers.md)** — Automatic failover to backup LLM providers when your primary model encounters errors, including independent fallback for auxiliary tasks like vision and compression.
+- **[API Server](api-server.md)** — Expose Hermes as an OpenAI-compatible HTTP endpoint. Connect any frontend that speaks the OpenAI format — Open WebUI, LobeChat, LibreChat, and more.
+- **[IDE Integration (ACP)](acp.md)** — Use Hermes inside ACP-compatible editors such as VS Code, Zed, and JetBrains. Chat, tool activity, file diffs, and terminal commands render inside your editor.
+- **[Honcho Memory](honcho.md)** — AI-native persistent memory for cross-session user modeling and personalization via dialectic reasoning.
+- **[RL Training](rl-training.md)** — Generate trajectory data from agent sessions for reinforcement learning and model fine-tuning.
+
 ## Customization
 
 - **[Personality & SOUL.md](personality.md)** — Fully customizable agent personality. `SOUL.md` is the primary identity file — the first thing in the system prompt — and you can swap in built-in or custom `/personality` presets per session.