fix: enforce strict config validation

docs/gateway/configuration.md

@@ -17,6 +17,19 @@ If the file is missing, Clawdbot uses safe-ish defaults (embedded Pi agent + per
 
 > **New to configuration?** Check out the [Configuration Examples](/gateway/configuration-examples) guide for complete examples with detailed explanations!
 
+## Strict config validation
+
+Clawdbot only accepts configurations that fully match the schema.
+Unknown keys, malformed types, or invalid values cause the Gateway to **refuse to start** for safety.
+
+When validation fails:
+- The Gateway does not boot.
+- Only diagnostic commands are allowed (for example: `clawdbot doctor`, `clawdbot logs`, `clawdbot health`, `clawdbot status`, `clawdbot service`, `clawdbot help`).
+- Run `clawdbot doctor` to see the exact issues.
+- Run `clawdbot doctor --fix` (or `--yes`) to apply migrations/repairs.
+
+Doctor never writes changes unless you explicitly opt into `--fix`/`--yes`.
+
 ## Schema + UI hints
 
 The Gateway exposes a JSON Schema representation of the config via `config.schema` for UI editors.

docs/gateway/troubleshooting.md

@@ -326,6 +326,22 @@ Clawdbot keeps conversation history in memory.
 
 ## Common troubleshooting
 
+### “Gateway won’t start — configuration invalid”
+
+Clawdbot now refuses to start when the config contains unknown keys, malformed values, or invalid types.
+This is intentional for safety.
+
+Fix it with Doctor:
+```bash
+clawdbot doctor
+clawdbot doctor --fix
+```
+
+Notes:
+- `clawdbot doctor` reports every invalid entry.
+- `clawdbot doctor --fix` applies migrations/repairs and rewrites the config.
+- Diagnostic commands like `clawdbot logs`, `clawdbot health`, `clawdbot status`, and `clawdbot service` still run even if the config is invalid.
+
 ### “All models failed” — what should I check first?
 
 - **Credentials** present for the provider(s) being tried (auth profiles + env vars).