feat: add fleet presets, cached pickers, and harness sign-in

[OndrejDrapalik]

Summary

Fleet launches can reuse JSON rosters with per-member templates, models, reasoning and counts. Box and fleet popups paint cached input before resolving fresh choices, so opening and cancelling a picker stays responsive.

• Add fleet --file PATH, stdin JSON, named config-adjacent presets, and editable preset selection with p / Shift+P. Validate generated specifications before creating members.
• Cache picker inputs per worktree, warm them during startup and workspace creation, and refresh before confirmation. Warm first paint measured 40.5 ms median versus 206.5 ms originally; Escape measured 5-16 ms. Preserve arrows and Shift+Tab on modern Bash and macOS Bash 3.2.
• Derive model and effort choices from a generated harness catalog, validate per-box pins, and support repeated fleet members with individual pins. Show pending members while their worktrees and boxes start.
• Add plugin-owned Muse and Codex sign-in and Amp access-token connections, plus fixes to unattended agent seeding and credential discovery. Keep rotating Codex refresh tokens out of boxes.

Four commits separate authentication, catalogs, picker/fleet integration, and documentation. Shared files prevent a clean feature stack. The unused raw md.json research download and personal presets are excluded.

Test plan

• CLI suite: 409 passed, including JSON files/stdin, overrides, preset validation, and popup handoffs.
• Popup PTY suite on macOS Bash 3.2: 12 passed, including preset editing, invalid-preset recovery, Escape, arrows and Shift+Tab.
• Focused Node suite for fleet specifications, popups and the dashboard launcher: 20 passed.
• Rust: cargo fmt --check, cargo clippy --all-targets -- -D warnings, 33 tests, and release build of both binaries.
• Manifest/package version agreement and git diff --check.
• Three personal preset dry runs validate 2-, 3-, and 4-member rosters without creating anything.
• Full GitHub Actions matrix passes on f1c36a6: macOS and Ubuntu, Node 22 and 24. The ordinary-terminal PTY harness waits for Bash 3.2's one-second Escape discriminator before sending the next arrow; popup Escape latency checks remain unchanged.
• Live provisioning from a JSON preset was not exercised.