claude-obsidian: unattended overnight runs -- lock, URL fallback, config fix

Needed to leave a full backlog drain running unattended:

- Run lock (flock): enabling the timer fired an immediate catch-up run
  (Persistent=true) while a manual run was about to start; without a
  lock the two would race on state.json and usage.jsonl.
- OBSIDIAN_API_URL accepts a comma-separated list, first reachable wins,
  so the permanent address and an interim port-forward share one config.
- Fix: inline "# comments" in config.env were parsed into values, so
  BUDGET_USD_PER_RUN=0.50  # ... crashed float(). The shipped
  config.env.example had exactly that shape on several lines -- anyone
  copying it would have hit the crash. A '#' inside a value (URL fragment)
  still survives. Tested against both the example and a real config.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KF322NzozeaFjpgWvh4F4g

claude-obsidian/config.env.example

@@ -3,12 +3,15 @@
 
 # Obsidian Local REST API plugin -- the plain-HTTP server (Settings -> Local REST API ->
 # Enable HTTP server). Point this at wherever that port is reachable from this machine.
-OBSIDIAN_API_URL=http://obsidian.example.internal:27123
+# Several URLs, comma-separated, are tried in order -- e.g. a permanent address, then a port-forward.
+OBSIDIAN_API_URL=http://obsidian.example.internal:27123,http://127.0.0.1:27123
 OBSIDIAN_API_KEY_FILE=~/.config/claude-obsidian/api-key
 
 # Summarizer. claude-cli = headless `claude -p` on your own Claude plan (no API key needed).
 LLM_BACKEND=claude-cli
-LLM_MODEL=haiku
+LLM_MODEL=haiku       # sonnet writes noticeably sharper notes for ~1-3x the usage; set prices to match below
+# LLM_PRICE_IN_PER_M=1.0     # used only for the pre-call budget estimate (haiku list; sonnet 3.0 / 15.0)
+# LLM_PRICE_OUT_PER_M=5.0
 # CLAUDE_BIN=claude
 
 # Or any OpenAI-compatible endpoint (LiteLLM, a local model):