feat(init): wire --llm flag and convo_scanner into discover_entities

Extends the init orchestrator to consume two new signal sources:

1. Claude Code conversation dirs: when the target is a
   `~/.claude/projects/` root, convo_scanner contributes ProjectInfo
   entries alongside the git/manifest projects. Dedup is by name,
   preferring the entry with more user-authored activity.
2. Optional LLM refinement: when --llm is passed, discover_entities
   constructs the provider, validates availability, and runs
   llm_refine.refine_entities on the merged candidates. Status
   summary (reclassified / dropped / cancelled / batch errors)
   prints to stderr.

New init flags (opt-in, default remains zero-API):
- --llm: enable refinement
- --llm-provider: ollama (default) | openai-compat | anthropic
- --llm-model: default gemma4:e4b for Ollama
- --llm-endpoint: URL (required for openai-compat)
- --llm-api-key: falls back to env ($ANTHROPIC_API_KEY or
  $OPENAI_API_KEY depending on provider)

Provider check_available runs before the scan, so the user sees an
immediate error ("Run: ollama pull <model>" or "ANTHROPIC_API_KEY not
set") rather than a mid-scan failure.

uv.lock

@@ -1174,6 +1174,7 @@ source = { editable = "." }
 dependencies = [
     { name = "chromadb" },
     { name = "pyyaml" },
+    { name = "tomli", marker = "python_full_version < '3.11'" },
 ]
 
 [package.optional-dependencies]
@@ -1206,6 +1207,7 @@ requires-dist = [
     { name = "pytest-cov", marker = "extra == 'dev'", specifier = ">=4.0" },
     { name = "pyyaml", specifier = ">=6.0,<7" },
     { name = "ruff", marker = "extra == 'dev'", specifier = ">=0.4.0" },
+    { name = "tomli", marker = "python_full_version < '3.11'", specifier = ">=2.0.0" },
 ]
 provides-extras = ["dev", "spellcheck"]