Add status, edit, open, and reset commands with agent config and updated docs

[milldr]

Summary

This PR adds several new commands, introduces the status resolution system, and overhauls documentation with spec references, GIF demos, and an updated README.

New commands

• flow status [workspace] — Resolves and displays the status of each repo in a workspace using shell-based check commands defined in a status spec (status.yaml). Without arguments, shows a summary table of all workspaces. With a workspace argument, shows a per-repo breakdown.
• flow edit <target> [workspace] — Opens config, state, or status files in $EDITOR for quick editing. Subcommands: flow edit config, flow edit state <ws>, flow edit status [ws].
• flow open <workspace> — Launches a new interactive shell session in the workspace directory. Sets iTerm2 tab color and title.
• flow reset <target> — Resets config files to their default values with a confirmation prompt (--force to skip). Subcommands:
  • flow reset status — Reset global status spec
  • flow reset config — Reset global config (restores default agent list)
  • flow reset state <ws> — Reset workspace state (preserves name/description)
  • flow reset skills — Reset shared agent skills (CLAUDE.md, flow-cli, workspace-structure) to embedded defaults

Status resolution system

• internal/status/ — New package implementing spec loading, validation, and resolution. Checks run top-to-bottom per repo; first passing check wins. Workspace status = least-advanced repo.
• 4-status default workflow — closed → in-review → in-progress → open, using gh, git, and jq shell checks.
• Workspace-level overrides — ~/.flow/workspaces/<id>/status.yaml fully replaces the global spec when present.
• Environment variables — Check commands receive FLOW_REPO_URL, FLOW_REPO_BRANCH, FLOW_REPO_PATH, FLOW_REPO_SLUG, FLOW_WORKSPACE_ID, FLOW_WORKSPACE_NAME.

Agent config and exec

• spec.agents[] in config.yaml — Configurable AI agent list with name, exec, and default fields. Claude is the default agent on fresh installs.
• Agent-aware flow exec — Running flow exec <ws> without -- launches the default agent. Multiple agents prompt for selection.

Config and path changes

• config.yaml — New global config file with flow/v1 schema, created automatically on first run.
• status.yaml — Global status spec, also auto-created on first run.
• WorkspaceStatusSpecPath and StatusSpecFile added to Config for status spec resolution.

Documentation

• Spec references — Added docs/specs/ with config, state, and status schema docs.
• PRDs — Added PRD-006 (status) and PRD-007 (edit command).
• Command docs — Auto-generated markdown for all new commands with GIF demos injected by gendocs.
• VHS tapes — New tapes for status, edit-config, edit-state, edit-status, open, reset-status, reset-config, reset-state, reset-skills, and delete.
• README — Restructured quickstart with collapsible sections, added motivation, updated directory layout, documented agent-aware exec.
• Skill doc — Updated flow-cli/SKILL.md with open and all reset subcommands.

Bug fixes

• In-progress detection — Fixed status check to ignore repos that are behind remote (only detect ahead-of-remote as in-progress).
• Status UI — Removed extra newline between status label and repo table.

Test plan

• make build && make lint && make test — all pass, 0 lint issues
• Status resolution: first-match wins, workspace = least-advanced repo
• Agent config: round-trip YAML, default agent selection, no-default handling
• flow reset <target> --force skips confirmation and resets file
• flow reset state preserves workspace name/description
• flow reset skills overwrites shared agent files with embedded defaults
• flow open spawns shell in correct workspace directory
• flow status with missing spec suggests flow reset status
• Demo tapes render correctly with pre-populated workspaces

🤖 Generated with Claude Code