feat(command): add plan-goal + execute-goal slash commands

[bborbe]

Summary

Adds the goal-side planning and execution gates — /vault-cli:plan-goal and /vault-cli:execute-goal — mirroring the task-side plan-task/execute-task. Together they complete the phase-gated goal lifecycle on top of the phase field shipped in v0.100.0. Part of the [[Phase-Gated Goal Flow]] goal.

What

• commands/plan-goal.md — planning gate. Validates the required decision sections (# Success Criteria / # Definition of Done / # Non-goals) and that every # Tasks wikilink resolves to an existing task file (skipping inline-code spans, stripping |alias). Runs goal-auditor, conversationally fills gaps, leaves the goal at phase: planning, hands off to execute-goal. Never flips phase itself.
• commands/execute-goal.md — execution gate + task-drain driver. Re-runs plan-goal's 3 hard checks, flips phase: planning → execution on a clean plan, then recommends the next open task — the first # Tasks wikilink whose linked task file is not completed/aborted — one at a time until the goal drains, then points to verify-goal → complete-goal. Recommends only; never runs the task (the normal task lifecycle does the work in between).
• README command table + CHANGELOG updated.

Design notes

• Both commands are inline (not sub-agents) — they read the parent conversation for goal detection, same justified exception as plan-task/execute-task.
• Task completion is derived from each linked task file's status, not stored on the goal — single source of truth, goal auto-reflects task progress.
• The 3 hard checks are duplicated inline in both commands (not shared) — same self-contained pattern as plan-task/execute-task.

Review

• make precommit green (lint 0 issues, tests, security, CHANGELOG valid).
• Both commands audited by coding:slash-command-auditor: plan-goal's forward-reference to execute-goal resolved by shipping both together; execute-goal 8/10 with the dangling-wikilink / empty-tasks / wording fixes applied.
• Plugin-only change → autoRelease bumps the 4 version strings post-merge.

[ben-s-pull-request-reviewer]

Based on my review of the PR, here are my findings:

Files Changed:

• CHANGELOG.md - New ## Unreleased entries for the two features
• README.md - Added plan-goal and execute-goal to the command table
• commands/plan-goal.md - New slash command definition
• commands/execute-goal.md - New slash command definition

Review Analysis:

1. Wikilink parsing - The |alias strip rule ([[Real Title|shown]] → Real Title) is correctly implemented per the spec. No nested pipe edge cases observed in the implementation.

2. Task file existence validation - Both commands use Glob to verify task files exist before claiming valid, which is correct.

3. Phase transition atomicity - vault-cli goal set "<name>" phase execution is a single atomic write operation, not a read-modify-write cycle, so there's no race condition concern.

4. Status normalization - The vault-cli task get command path goes through domain.NormalizeTaskStatus() which correctly maps legacy values like todo → next, so the status comparison logic is sound.

5. Test coverage - These are Claude Code plugin slash commands (markdown definitions), not Go code. The underlying Go operations they call (goal_workon, goal_complete, etc.) have existing test coverage. No new Go code was added that requires tests.

6. Security - Commands read from local vault filesystem; wikilink resolution is filesystem-based with no network exposure.

No critical issues found.

{
  "verdict": "approve",
  "summary": "The plan-goal and execute-goal slash commands are well-designed additions that properly gate goal lifecycle transitions, correctly implement wikilink parsing with alias stripping, and integrate cleanly with existing vault-cli infrastructure. No security, correctness, or test coverage issues identified.",
  "comments": [],
  "concerns_addressed": [
    "correctness: wikilink alias stripping correctly handles [[Real Title|alias]] format - no nested pipe edge case found in scope",
    "correctness: task file existence validation implemented via Glob before claiming valid (plan-goal step 5, execute-goal step 5)",
    "correctness: phase transition uses atomic vault-cli goal set operation, not read-modify-write - no race condition",
    "correctness: status values normalized via domain.NormalizeTaskStatus() which maps todo→next and other aliases",
    "tests: slash commands are Claude Code plugin definitions (markdown), not Go code - underlying operations have existing test coverage",
    "security: wikilink resolution reads local vault filesystem only, no sensitive data exposure"
  ]
}