refactor(logs): nest hook output by branch/source/hook-type/name

[max-sixty]

Flattens categorization of .git/wt/logs/ by making the filesystem encode what the old scheme crammed into filenames.

Layout: top-level files are shared logs (commands.jsonl*, verbose.log, diagnostic.md); top-level directories are per-branch log trees — {branch}/{source}/{hook-type}/{name}.log for hook output, {branch}/internal/remove.log for background removal, wt/internal/trash-sweep.log for the trash sweeper. Categorization becomes a trivial file-vs-directory check, eliminating the exclusion rule ends_with(".log") && !is_diagnostic_file(name).

Wins: per-branch listing/clearing is now O(that branch) instead of O(all logs); orphan cleanup for a removed branch is a single remove_dir_all; filenames drop the joined-tuple collision hashes they only needed to disambiguate flat keys.

Transition: clear_logs keeps a self-healing sweep of legacy top-level .log files so users transition without an explicit migration. A pinning test (test_state_clear_logs_sweeps_legacy_flat_files) guards that behavior.

Observable change: logs get --format=json now puts relative paths in the file field (e.g. main/user/post-start/server.log). Log locations are listed as "flexible" in CLAUDE.md, so this is in scope.

Reviewer orientation:

• src/commands/process.rs — HookLog::path() rewritten; suffix() / filename() deleted.
• src/commands/config/state.rs — new walk_hook_output_files / walk_branch_dir / HookOutputEntry; clear_logs handles legacy sweep; partition_log_files_json + render_* split along the top-level vs hook-output seam; module docstring pins the invariant.
• src/testing/mod.rs — wait_for_file_count walks recursively.
• Test fixtures in tests/integration_tests/config_state.rs use new hook_log_rel_path / internal_log_rel_path / write_log_at helpers.

🤖 Generated with Claude Code

[worktrunk-bot]

Two issues found:

Garbled doc comment on log_path_for_debug — The new function was inserted between the tail of create_detach_log's doc comment and create_detach_log itself, so log_path_for_debug absorbs text that belongs to create_detach_log ("Create the log directory and file...", "Returns (log_path, log_file). Shared by..."). create_detach_log ends up with no doc comment. Fix: move log_path_for_debug and its doc block to after create_detach_log.

Trash-sweep log path wrong in docs — docs/content/remove.md, src/cli/mod.rs, and skills/worktrunk/reference/remove.md all say .git/wt/logs/wt/internal/trash-sweep.log, but sanitize_for_filename("wt") produces wt-boj (confirmed by the snapshot in test_hook_log_path), so the actual path is .git/wt/logs/wt-boj/internal/trash-sweep.log. See inline suggestion on docs/content/remove.md.

[worktrunk-bot]

The previous CI run (d6456bc) had two failures I investigated:

1. test_help::case_11 (snapshot help_remove_long) — already resolved by your commit f96b126 (sync after wording merge).

2. Four Windows test failures in test_state_logs_get_hook_* — these are still present. The root cause is println\!("{}", log_path.display()) in handle_logs_get (state.rs:483): on Windows display() emits backslashes, so stdout.contains("branch/user/hook-type/name.log") always fails. path_slash::PathExt was already imported; I switched to to_slash_lossy() in c30d804.