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/user-guide/features/fallback-providers.md

@@ -156,7 +156,7 @@ Hermes uses separate lightweight models for side tasks. Each task has its own pr
 |------|-------------|-----------|
 | Vision | Image analysis, browser screenshots | `auxiliary.vision` |
 | Web Extract | Web page summarization | `auxiliary.web_extract` |
-| Compression | Context compression summaries | `auxiliary.compression` or `compression.summary_provider` |
+| Compression | Context compression summaries | `auxiliary.compression` |
 | Session Search | Past session summarization | `auxiliary.session_search` |
 | Skills Hub | Skill search and discovery | `auxiliary.skills_hub` |
 | MCP | MCP helper operations | `auxiliary.mcp` |
@@ -219,13 +219,14 @@ auxiliary:
     model: ""
 ```
 
-Every task above follows the same **provider / model / base_url** pattern. Context compression uses its own top-level block:
+Every task above follows the same **provider / model / base_url** pattern. Context compression is configured under `auxiliary.compression`:
 
 ```yaml
-compression:
-  summary_provider: main                             # Same provider options as auxiliary tasks
-  summary_model: google/gemini-3-flash-preview
-  summary_base_url: null                             # Custom OpenAI-compatible endpoint
+auxiliary:
+  compression:
+    provider: main                                    # Same provider options as other auxiliary tasks
+    model: google/gemini-3-flash-preview
+    base_url: null                                    # Custom OpenAI-compatible endpoint
 ```
 
 And the fallback model uses:
@@ -270,15 +271,18 @@ auxiliary:
 
 ## Context Compression Fallback
 
-Context compression has a legacy configuration path in addition to the auxiliary system:
+Context compression uses the `auxiliary.compression` config block to control which model and provider handles summarization:
 
 ```yaml
-compression:
-  summary_provider: "auto"                    # auto | openrouter | nous | main
-  summary_model: "google/gemini-3-flash-preview"
+auxiliary:
+  compression:
+    provider: "auto"                              # auto | openrouter | nous | main
+    model: "google/gemini-3-flash-preview"
 ```
 
-This is equivalent to configuring `auxiliary.compression.provider` and `auxiliary.compression.model`. If both are set, the `auxiliary.compression` values take precedence.
+:::info Legacy migration
+Older configs with `compression.summary_model` / `compression.summary_provider` / `compression.summary_base_url` are automatically migrated to `auxiliary.compression.*` on first load (config version 17).
+:::
 
 If no provider is available for compression, Hermes drops middle conversation turns without generating a summary rather than failing the session.
 
@@ -325,7 +329,7 @@ See [Scheduled Tasks (Cron)](/docs/user-guide/features/cron) for full configurat
 | Main agent model | `fallback_model` in config.yaml — one-shot failover on errors | `fallback_model:` (top-level) |
 | Vision | Auto-detection chain + internal OpenRouter retry | `auxiliary.vision` |
 | Web extraction | Auto-detection chain + internal OpenRouter retry | `auxiliary.web_extract` |
-| Context compression | Auto-detection chain, degrades to no-summary if unavailable | `auxiliary.compression` or `compression.summary_provider` |
+| Context compression | Auto-detection chain, degrades to no-summary if unavailable | `auxiliary.compression` |
 | Session search | Auto-detection chain | `auxiliary.session_search` |
 | Skills hub | Auto-detection chain | `auxiliary.skills_hub` |
 | MCP helpers | Auto-detection chain | `auxiliary.mcp` |