Unify logging into single typed JSONL logger

[waltoss]

Summary

Replace 3 separate logging mechanisms (CdpLogger, DaemonLogger, DEBUG_DAP env var) with a single unified structured logger that writes all sources to one JSONL file per session.

Before

• 2 log files per session: <session>.cdp.log + <session>.daemon.log
• 3 logging systems: CdpLogger (protocol traffic), DaemonLogger (app events), DEBUG_DAP=1 (DAP to stderr)
• No type safety on log data — any object accepted
• Confusing UX: dbg logs vs dbg logs --daemon to switch between files
• No DAP file logging — only stderr passthrough

// Before: 3 different APIs
this.cdpLogger.logSend(id, method, params);
this.daemonLogger.info("child.spawn", "Spawned process", { pid });
if (DEBUG_DAP) process.stderr.write(`[DAP] ${msg}\n`);

After

• 1 log file per session: <session>.log
• 1 typed logger with scoped children: Logger<"cdp">, Logger<"dap">, Logger<"session">
• Compile-time type safety via LogData<N, M> conditional type — known messages enforce exact data shapes, unknown messages accept Record<string, unknown>
• Unified viewer: dbg logs --src cdp --level debug with colored output and custom formatters per (source, message) pair
• DAP protocol logging to file (trace level)

// After: one API, typed per source
const log = rootLogger.child("session");
log.info("child.spawn", { pid: 1234 });  // ✓ typed — pid required

const cdp = rootLogger.child("cdp");
cdp.trace("send", { method: "Debugger.pause", id: 5 });  // ✓ typed
cdp.trace("send", { method: "Debugger.pause" });          // ✗ compile error — missing id
cdp.debug("custom", { anything: true });                   // ✓ open fallback

dbg logs output (with colors)

10:34:35.715 TRACE cdp      → Debugger.pause
10:34:35.727 TRACE cdp      ← Debugger.pause #5 ✓ (12ms)
10:34:35.728 TRACE cdp      ⚡ Debugger.paused
10:34:35.730 INFO  session   child.spawn pid=1234
10:34:35.731 INFO  session   state.change from=idle to=paused

Test plan

• 531 tests pass (all existing tests)
• Typecheck clean
• Lint clean
• Unit tests updated for new logger API
• Integration tests verify CDP, session, and process lifecycle logging

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