Logging overhaul: per-task log files, daemon.log drill-down

Switch from jobkit-daemon crate to jobkit with daemon feature.
Wire up per-task log files for all daemon-spawned agent tasks.

Changes:
- Use jobkit::daemon:: instead of jobkit_daemon::
- All agent tasks get .log_dir() set to $data_dir/logs/
- Task log path shown in daemon status and TUI
- New CLI: poc-memory agent daemon log --task NAME
  Finds the task's log path from status or daemon.log, tails the file
- LLM backend selection logged to daemon.log via log_event
- Targeted agent job names include the target key for debuggability
- Logging architecture documented in doc/logging.md

Two-level logging, no duplication:
- daemon.log: lifecycle events with task log path for drill-down
- per-task logs: full agent output via ctx.log_line()

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

poc-memory/Cargo.toml

@@ -19,8 +19,7 @@ memmap2 = "0.9"
 rayon = "1"
 peg = "0.8"
 paste = "1"
-jobkit = { git = "https://evilpiepirate.org/git/jobkit.git/" }
-jobkit-daemon = { git = "https://evilpiepirate.org/git/jobkit-daemon.git/" }
+jobkit = { path = "/home/kent/jobkit", features = ["daemon"] }
 poc-agent = { path = "../poc-agent" }
 tokio = { version = "1", features = ["rt-multi-thread"] }
 redb = "2"