feat(cli): Add verbosity controls, JSON log format, and triple-layer subscriber

Overhaul the CLI logging infrastructure for production observability:

CLI flags:
- Add -v/-vv/-vvv (--verbose) for progressive stderr verbosity control:
  0=INFO, 1=DEBUG app, 2=DEBUG all, 3+=TRACE
- Add --log-format text|json for structured stderr output in automation
- Existing -q/--quiet overrides verbosity for silent operation

Subscriber architecture (main.rs):
- Replace single-layer subscriber with triple-layer setup:
  1. stderr layer: human-readable or JSON, filtered by -v flags
  2. file layer: always-on JSON to daily-rotated logs (lore.YYYY-MM-DD.log)
  3. MetricsLayer: captures span timing for robot-mode performance payloads
- Parse CLI before subscriber init so verbosity is known at setup time
- Load LoggingConfig early (with graceful fallback for pre-init commands)
- Clean up old log files before subscriber init to avoid holding deleted handles
- Hold WorkerGuard at function scope to ensure flush on exit

Doctor command:
- Add logging health check: validates log directory exists, reports file
  count and total size, warns on missing or inaccessible log directory

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/cli/mod.rs

@@ -31,6 +31,14 @@ pub struct Cli {
     #[arg(short = 'q', long, global = true)]
     pub quiet: bool,
 
+    /// Increase log verbosity (-v, -vv, -vvv)
+    #[arg(short = 'v', long = "verbose", action = clap::ArgAction::Count, global = true)]
+    pub verbose: u8,
+
+    /// Log format for stderr output: text (default) or json
+    #[arg(long = "log-format", global = true, value_parser = ["text", "json"], default_value = "text")]
+    pub log_format: String,
+
     #[command(subcommand)]
     pub command: Commands,
 }