docs: comprehensive update for recent merged PRs (#9019)

Audit and update documentation across 12 files to match changes from
~50 recently merged PRs. Key updates:

Slash commands (slash-commands.md):
- Add 5 missing commands: /snapshot, /fast, /image, /debug, /restart
- Fix /status incorrectly labeled as messaging-only (available in both)
- Add --global flag to /model docs
- Add [focus topic] arg to /compress docs

CLI commands (cli-commands.md):
- Add hermes debug share section with options and examples
- Add hermes backup section with --quick and --label flags
- Add hermes import section

Feature docs:
- TTS: document global tts.speed and per-provider speed for Edge/OpenAI
- Web dashboard: add docs for 5 missing pages (Sessions, Logs,
  Analytics, Cron, Skills) and 15+ API endpoints
- WhatsApp: add streaming, 4K chunking, and markdown formatting docs
- Skills: add GitHub rate-limit/GITHUB_TOKEN troubleshooting tip
- Budget: document CLI notification on iteration budget exhaustion

Config migration (compression.summary_* → auxiliary.compression.*):
- Update configuration.md, environment-variables.md,
  fallback-providers.md, cli.md, and context-compression-and-caching.md
- Replace legacy compression.summary_model/provider/base_url references
  with auxiliary.compression.model/provider/base_url
- Add legacy migration info boxes explaining auto-migration

Minor fixes:
- wecom-callback.md: clarify 'text only' limitation (input only)
- Escape {session_id}/{job_id} in web-dashboard.md headings for MDX

website/docs/developer-guide/context-compression-and-caching.md

@@ -84,7 +84,13 @@ compression:
   threshold: 0.50            # Fraction of context window (default: 0.50 = 50%)
   target_ratio: 0.20         # How much of threshold to keep as tail (default: 0.20)
   protect_last_n: 20         # Minimum protected tail messages (default: 20)
-  summary_model: null        # Override model for summaries (default: uses auxiliary)
+
+# Summarization model/provider configured under auxiliary:
+auxiliary:
+  compression:
+    model: null              # Override model for summaries (default: auto-detect)
+    provider: auto           # Provider: "auto", "openrouter", "nous", "main", etc.
+    base_url: null           # Custom OpenAI-compatible endpoint
 ```
 
 ### Parameter Details