feat(logging): configurable format (text|jsonl) + unified hub/agent log config (#51)

[oorabona]

Closes #51.

What & why

Harmonize logging configuration across the hub (TypeScript) and the agent (Rust): one [logging]
contract — consistent level, a configurable format (text | jsonl), consistent semantics — for
easier debugging and log aggregation (one parser for Loki/Vector/ELK, correlatable hub↔agent logs).

The hub already parsed [logging] (level / output / rotation) but had no format; the agent already had
both tracing formatters (json/text) but hardcoded by daemon-vs-foreground and took its level from
RUST_LOG only. This unifies them.

Design — DRY the contract, native implementations

Hub is TS, agent is Rust → no shared runtime, so the DRY is a single documented contract, implemented
twice (no codegen/shared-schema machinery for a few fields).

• shared/hub: format = "text" | "jsonl" (default jsonl) added to LogConfig + extractLogConfig;
  extractAgentConfig derives the agent's level + format from the same [logging] section, with
  defensive type-guards (a malformed [agent]/[logging] value falls back to defaults instead of
  crashing hub startup).
• HubLogger: the API-backing log file (hub.jsonl, read by /api/logs) is always JSONL;
  format governs the stderr/console rendering (structured-to-file, pretty-to-console). Enabling
  format=text never blinds the in-app log viewer or file-tailing aggregators.
• agent (Rust): tracing_subscriber is driven by config-supplied --log-level + --format
  (formatters already existed); config level is honored when RUST_LOG is unset (RUST_LOG still
  overrides). Default jsonl preserved.
• delivery: the hub passes --log-level/--format to the local daemon (agent-launcher) and to
  remote agents — OS-aware (POSIX single-quote for Unix, cmd.exe %VAR%+double-quote for
  Windows, matching the existing deploy convention) and only to agents the hub deployed this session
  (known-current binary); found/pre-existing remote agents run --stdio only, preserving back-compat.
  server.ts now forwards the parsed agent config into SessionManager (closing an existing gap).
• Contract documented once in docs/plans/logging-daemon.md + docs/SPEC.md.

Behavior-preserving by default (jsonl).

Verification

• TS: vitest packages/hub packages/shared → 1663 passed / 2 skipped / 0 failed; biome + tsc clean; no
  new skips.
• Rust: cargo fmt --check, cargo clippy -p termora-agent -- -D warnings, cargo test -p termora-agent
  (82 tests) → green.
• Hardened across several orthogonal-gate rounds (codex). The gate caught and we fixed: text format
  blinding the log API; a malformed-TOML hub-startup crash exposed by wiring the agent config; unquoted
  remote exec path; POSIX-only quoting breaking Windows remotes; new args breaking older remote agents.

Gate status (degraded GATE_OK — documented)

Final gate on the head: codex = CLEAN; copilot exogenously unavailable (rate-limited / à sec)
across these runs. Per the gate's set-union semantics a single CLEAN satisfies when the other engine is
exogenously down.