refactor(cli): replace hand-rolled parsers with effect/unstable/cli

[FreshlyBrewedCode]

Part of #32 · Closes #33

src/cli.ts hand-rolled four argument parsers that disagreed with each other: parseFlags walks
argv at stride 2 and structurally cannot represent a boolean flag, which is why factory start
needed a second, different parser; init's flags were parsed inline in the import.meta.main
block; and parseServeArgs passed an unvalidated Number(portRaw) straight to Bun.serve, so
--port abc became NaN. Because usageError called process.exit inside a parser, none of it
could be tested — every existing CLI test bypassed argv and called the command functions directly
with structured options. This PR replaces all four parsers and the hand-maintained USAGE string
with a single effect/unstable/cli command tree, per ADR 0009 §5.

What changed

• New src/cli-commands.ts defines factoryCommand — a root Command with six subcommands
  (init, serve, start, runs, log, run), each with typed Flag/Argument definitions,
  descriptions, and defaults matching the old USAGE string.
• src/cli.ts drops USAGE, usageError, parseFlags, parseArgs, parseStartArgs, and
  parseServeArgs entirely. The import.meta.main block now runs Command.run(factoryCommand, …)
  under a CliEnvLayer (FileSystem.layerNoop, Path.layer, Stdio.layerTest seeded with real
  process.argv, a Terminal shim, and a ChildProcessSpawner shim).
  runCli/startCli/listRunsCli/logRunCli — the command bodies — are unchanged.
• --port is now Flag.Int, so a non-numeric value is rejected at parse time with a clear error
  instead of reaching Bun.serve as NaN.
• Exit code fix: Command.run fails with CliError.ShowHelp both for genuine parse errors and
  for "no subcommand given" / explicit --help (help renders from the command definition either
  way). ShowHelp.errors distinguishes the two — empty means help was all that happened. The
  import.meta.main catch now only calls process.exit(1) when that array is non-empty, so bare
  factory, --help, and -h exit 0 again (matching the pre-effect/unstable/cli behaviour),
  while --port abc, unknown flags, and missing required args/flags still exit 1.
• New src/cli-argv.test.ts (28 tests) feeds argv arrays straight into a Command, covering
  defaults, required flags/arguments, the --watch boolean, the --clone/--git-name/
  --git-email group, --port rejecting non-numeric input, generated --help at the root and per
  subcommand, unknown-flag rejection, and — since the exit-code mapping lives in cli.ts's
  import.meta.main block, only observable by actually running the binary — a subprocess-spawned
  suite pinning the no-args/--help/-h exit code and confirming --port abc/unknown flags still
  exit non-zero.

Notes for reviewers

• Help text is now generated from the Command/Flag/Argument definitions (with
  Command.withDescription/Flag.withDescription) rather than hand-maintained, and the library
  adds global flags the old CLI never had (--version, --wizard, --completions,
  --log-level) — out of scope for Parse CLI arguments with effect/unstable/cli #33, not regressions.
• CliEnvLayer in src/cli.ts reuses the effect/cli library's own test-fixture layer shape
  (Stdio.layerTest, Terminal.make with readInput/readLine: Effect.die, a
  ChildProcessSpawner that dies on use) as the production entrypoint's environment. I checked
  whether a real platform layer exists to swap it for: effect@4.0.0-rc.115 exports no such thing
  — no @effect/platform-node/@effect/platform-bun equivalent is installed, and Stdio,
  Terminal, FileSystem, and ChildProcessSpawner in this rc only ship test/noop constructors.
  So CliEnvLayer stays as-is; I added a comment on it explaining why and which paths (--wizard,
  anything reading stdin, anything shelling out through ChildProcessSpawner) would hit a bare
  Effect.die("unused") if ever exercised. Everything this PR's commands do goes through
  Console for output and real process.argv for input, so it's unaffected.
• All process.exit calls that remain (cli-commands.ts, plus logRunCli's in cli.ts, plus the
  single process.exit(1) in the import.meta.main catch) are outside argv parsing — satisfies
  the "no process.exit in a parsing function" criterion.
• The exit-code fix deliberately does not use Effect.runPromiseExit +
  Runtime.defaultTeardown/makeRunMain (effect's usual main-entrypoint helper): that teardown
  calls process.exit(0) on any successful Effect completion, but factory serve's handler
  effect resolves right after starting the long-lived HTTP server — forcing an exit there would
  kill the daemon immediately after startup. The fix stays inside the existing .catch() shape
  instead, so a successful run still falls through to whatever keeps (or doesn't keep) the process
  alive on its own.

Verification

• bun run check (format:check + lint + typecheck + bun test) passes locally: 289 pass, 0 fail.
• Manually ran a matrix of hand invocations (bare factory, --help, -h, serve --help,
  serve --port abc, serve --nope, unknown subcommand, missing required flag/argument,
  $FACTORY_URL fallback, --clone/--git-name/--git-email) and confirmed exit codes and
  stdout/stderr routing match the pre-effect/unstable/cli CLI.
• Manually started factory serve --port 0 and confirmed it stays listening (doesn't exit after
  startup) under the new exit-code handling.
• I did not additionally run bun run test:e2e.

Stack

1. refactor(cli): replace hand-rolled parsers with effect/unstable/cli #52 — 33-parse-cli-with-effect-cli (issue Parse CLI arguments with effect/unstable/cli #33) ← you are here
2. refactor(errors): represent domain failures as Schema.TaggedError #53 — 34-domain-errors-as-tagged-errors (issue Represent domain failures as Schema.TaggedError #34)
3. refactor(runtime): move chunk interpretation into the agent adapter #54 — 35-move-chunk-interpretation-into-adapter (issue Move chunk interpretation into the agent adapter #35)
4. refactor(runtime): move headless permission setup into the agent adapter #55 — 37-move-headless-permissions (issue Move headless permission setup out of the workspace allocator #37)
5. feat(runtime): add Effect composition root and agent runtime service #56 — 36-agent-runtime-service (issue Add an Effect composition root and make the agent runtime a service #36)
6. refactor(daemon): move singletons into per-daemon layers #57 — 38-move-singletons-into-layers (issue Move the daemon's remaining singletons into layers #38)

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