fix: review fixes for PRs #1 and #2

PR #1 (LlmProvider + OAuth) fixes:
- Move provider selection from [bifrost].provider to [inference].provider
  (Bifrost is a provider, not the parent category — they are peers)
- Add Inference category to settings TUI with provider picker
- Wire build_provider() into CLI/chat/model-refresh paths so OAuth
  works outside server mode
- Update ServerConversation to use Arc<dyn LlmProvider> for consistency

PR #2 (web UI) assessment:
- Remove entire web/ directory — not aligned with substrate ethos
  (client-side compaction model contradicts Constitution Article IV;
   autoCommit toggle misunderstands git-backed memory physics;
   vocabulary doesn't match project architecture)
- Keep the 3 new REST endpoints (config, compaction-logs, token metrics)
- Revert run_reflect path change (keep canonical ~/.souveraine/agents/)
- Delete souveraine_fixes.patch (dev artifact)
- Restore demo example (was commented out as workaround for missing file)
- Copy examples/demo.rs from primary branch (was never pushed to public)

Tests: 184 passed, 0 failed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

souveraine.example.toml

@@ -1,19 +1,21 @@
 # Souveraine Configuration
 # Everything is modular — enable/disable components as needed
 
-# === BIFROST INFERENCE ===
-[bifrost]
-# Active provider implementation:
-#   "bifrost"      (default) — any OpenAI-compatible gateway via base_url below.
+# === INFERENCE PROVIDER ===
+# Select which provider answers model calls.
+#   "bifrost"      (default) — OpenAI-compatible gateway (see [bifrost] section below).
 #   "openai-oauth"           — ride the Codex CLI's ChatGPT login (run
 #                              `codex login` first); drives
 #                              chatgpt.com/backend-api/codex/responses with no
-#                              API key. base_url/api_key/virtual_key are ignored
+#                              API key. [bifrost] base_url/api_key/virtual_key are ignored
 #                              in this mode; set primary_model to a ChatGPT model
 #                              (e.g. "gpt-5.5"). Bifrost-namespaced ids are
 #                              tolerated and mapped to the provider default.
+[inference]
 # provider = "bifrost"
 
+# === BIFROST PROVIDER ===
+[bifrost]
 # Bifrost is the OpenAI-compatible API gateway
 base_url = "http://127.0.0.1:3360"
 api_key = ""  # Set via `souveraine auth set` or BIFROST_KEY env var