feat(ultraplan-local)!: v2.0.0 — brief-driven four-command pipeline

Extract interview from /ultraplan-local into new /ultrabrief-local command.
/ultraplan-local now requires --brief or --project (breaking). All pipeline
artifacts land in one project directory: .claude/projects/{date}-{slug}/
with brief.md, research/, plan.md, sessions/, progress.json.

Breaking changes:
- /ultraplan-local requires --brief <path> or --project <dir>
- /ultraplan-local --spec removed (convert specs to briefs per MIGRATION.md)
- Interview phase moved to /ultrabrief-local
- spec-reviewer renamed to brief-reviewer with 5th dimension (Research Plan validity)

Added:
- /ultrabrief-local command (interactive interview → brief.md with research plan)
- templates/ultrabrief-template.md (task brief format with intent + research plan)
- brief-reviewer agent (5-dimension brief quality review)
- --project <dir> flag on /ultraresearch-local, /ultraplan-local, /ultraexecute-local
- MIGRATION.md (v1 → v2 upgrade guide)

Changed:
- planning-orchestrator accepts Brief file: input (was Spec file:)
- planning-orchestrator Phase 1b uses brief-reviewer
- README + CLAUDE.md rewritten for four-command pipeline and task/research brief terminology
- CHANGELOG.md [2.0.0] entry with rationale
- Marketplace root README + CLAUDE.md updated to v2.0.0

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

plugins/ultraplan-local/commands/ultraexecute-local.md

@@ -1,7 +1,7 @@
 ---
 name: ultraexecute-local
 description: Disciplined plan executor — single-session or multi-session with parallel orchestration, failure recovery, and headless support
-argument-hint: "[--fg | --resume | --dry-run | --validate | --step N | --session N] <plan.md>"
+argument-hint: "[--project <dir>] [--fg | --resume | --dry-run | --validate | --step N | --session N] [plan.md]"
 model: opus
 allowed-tools: Read, Write, Edit, Bash, Glob, Grep, AskUserQuestion
 ---
@@ -18,29 +18,49 @@ Designed to work identically in interactive and headless (`claude -p`) mode.
 
 Parse `$ARGUMENTS` for mode flags:
 
-1. If arguments contain `--fg`: extract the file path. Set **mode = foreground**.
-2. If arguments contain `--resume`: extract the file path. Set **mode = resume**.
-3. If arguments contain `--dry-run`: extract the file path. Set **mode = dry-run**.
-4. If arguments contain `--validate`: extract the file path. Set **mode = validate**.
-5. If arguments contain `--step N` (N is a positive integer): extract N and the file path.
+1. If arguments contain `--project <dir>`: extract the directory path.
+   - Resolve `{dir}` (trim trailing slash).
+   - Set **project_dir = {dir}**.
+   - Derive implicit file path: `{dir}/plan.md`.
+   - If `{dir}` does not exist or `{dir}/plan.md` is missing:
+     ```
+     Error: project directory missing plan.md: {dir}
+     Run /ultraplan-local --project {dir} to produce it.
+     ```
+   - If no explicit `<plan.md>` argument is provided after flag parsing,
+     use the derived `{dir}/plan.md`. If a `<plan.md>` argument IS provided,
+     use that path but keep `project_dir` set (user may be pointing at a
+     recovery session spec inside the project).
+   - Continue parsing remaining flags (they combine with `--project`).
+2. If arguments contain `--fg`: extract the file path. Set **mode = foreground**.
+3. If arguments contain `--resume`: extract the file path. Set **mode = resume**.
+4. If arguments contain `--dry-run`: extract the file path. Set **mode = dry-run**.
+5. If arguments contain `--validate`: extract the file path. Set **mode = validate**.
+6. If arguments contain `--step N` (N is a positive integer): extract N and the file path.
    Set **mode = step**, **target-step = N**.
-6. If arguments contain `--session N` (N is a positive integer): extract N and the file path.
+7. If arguments contain `--session N` (N is a positive integer): extract N and the file path.
    Set **mode = session**, **target-session = N**.
-7. Otherwise: the entire argument string is the file path. Set **mode = execute**.
+8. Otherwise: the entire argument string is the file path. Set **mode = execute**.
 
-If no path is provided, output usage and stop:
+If no path is provided (and `--project` was not used to derive one), output
+usage and stop:
 
 ```
 Usage: /ultraexecute-local <plan.md>
+       /ultraexecute-local --project <dir>
        /ultraexecute-local --fg <plan.md>
        /ultraexecute-local --resume <plan.md>
        /ultraexecute-local --dry-run <plan.md>
        /ultraexecute-local --validate <plan.md>
        /ultraexecute-local --step N <plan.md>
        /ultraexecute-local --session N <plan.md>
+       /ultraexecute-local --project <dir> --resume
+       /ultraexecute-local --project <dir> --session N
 
 Modes:
   (default)      Auto — multi-session if plan has Execution Strategy, else foreground
+  --project      Resolve plan.md inside an ultrabrief project folder; progress.json
+                 is written there too
   --fg           Force foreground — all steps sequentially, ignore Execution Strategy
   --resume       Resume from last progress checkpoint
   --dry-run      Validate plan and show execution strategy without running
@@ -50,6 +70,8 @@ Modes:
 
 Examples:
   /ultraexecute-local .claude/plans/ultraplan-2026-04-06-auth-refactor.md
+  /ultraexecute-local --project .claude/projects/2026-04-18-jwt-auth
+  /ultraexecute-local --project .claude/projects/2026-04-18-jwt-auth --resume
   /ultraexecute-local --fg .claude/plans/ultraplan-2026-04-06-auth-refactor.md
   /ultraexecute-local --session 2 .claude/plans/ultraplan-2026-04-06-auth-refactor.md
   /ultraexecute-local --dry-run .claude/plans/ultraplan-2026-04-06-auth-refactor.md
@@ -63,7 +85,8 @@ Error: file not found: {path}
 
 Report detected mode:
 ```
-Mode: {execute | resume | dry-run | step N}
+Mode: {execute | resume | dry-run | step N | session N}
+Project: {project_dir or "-"}
 File: {path}
 ```
 
@@ -634,12 +657,19 @@ need to know it is in a worktree — git handles this transparently.
 
 ## Phase 3 — Progress file setup
 
-The progress file lives at `{plan-dir}/.ultraexecute-progress-{slug}.json` where
-`{slug}` is the plan filename without extension.
+The progress file location depends on whether `--project` is in use:
 
-**Session-scoped naming:** When `mode = session N`, use
-`{plan-dir}/.ultraexecute-progress-{slug}-session-{N}.json` instead. This prevents
-merge conflicts when parallel sessions each write their own progress file.
+- **With `--project <dir>`:** progress lives at `{project_dir}/progress.json`.
+- **Without `--project`:** progress lives at
+  `{plan-dir}/.ultraexecute-progress-{slug}.json`, where `{slug}` is the plan
+  filename without extension.
+
+**Session-scoped naming:** When `mode = session N`:
+- With `--project`: `{project_dir}/progress-session-{N}.json`.
+- Without `--project`: `{plan-dir}/.ultraexecute-progress-{slug}-session-{N}.json`.
+
+This prevents merge conflicts when parallel sessions each write their own
+progress file.
 
 ### Progress file schema