feat: add /gsd-spec-phase — Socratic spec refinement with ambiguity scoring (#2213) (#2322)

Introduces `/gsd-spec-phase <phase>` as an optional pre-step before discuss-phase.
Clarifies WHAT a phase delivers (requirements, boundaries, acceptance criteria) with
quantitative ambiguity scoring before discuss-phase handles HOW to implement.

- `commands/gsd/spec-phase.md` — slash command routing to workflow
- `get-shit-done/workflows/spec-phase.md` — full Socratic interview loop (up to 6
  rounds, 5 rotating perspectives: Researcher, Simplifier, Boundary Keeper, Failure
  Analyst, Seed Closer) with weighted 4-dimension ambiguity gate (≤ 0.20 to write SPEC.md)
- `get-shit-done/templates/spec.md` — SPEC.md template with falsifiable requirements
  (Current/Target/Acceptance per requirement), Boundaries, Acceptance Criteria,
  Ambiguity Report, and Interview Log; includes two full worked examples
- `get-shit-done/workflows/discuss-phase.md` — new `check_spec` step detects
  `{padded_phase}-SPEC.md` at startup; displays "Found SPEC.md — N requirements
  locked. Focusing on implementation decisions."; `analyze_phase` respects `spec_loaded`
  flag to skip "what/why" gray areas; `write_context` emits `<spec_lock>` section
  with boundary summary and canonical ref to SPEC.md
- `docs/ARCHITECTURE.md` — update command/workflow counts (74→75, 71→72)

Closes #2213

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

commands/gsd/spec-phase.md

@@ -0,0 +1,62 @@
+---
+name: gsd:spec-phase
+description: Socratic spec refinement — clarify WHAT a phase delivers with ambiguity scoring before discuss-phase. Produces a SPEC.md with falsifiable requirements locked before implementation decisions begin.
+argument-hint: "<phase> [--auto] [--text]"
+allowed-tools:
+  - Read
+  - Write
+  - Bash
+  - Glob
+  - Grep
+  - AskUserQuestion
+---
+
+<objective>
+Clarify phase requirements through structured Socratic questioning with quantitative ambiguity scoring.
+
+**Position in workflow:** `spec-phase → discuss-phase → plan-phase → execute-phase → verify`
+
+**How it works:**
+1. Load phase context (PROJECT.md, REQUIREMENTS.md, ROADMAP.md, STATE.md)
+2. Scout the codebase — understand current state before asking questions
+3. Run Socratic interview loop (up to 6 rounds, rotating perspectives)
+4. Score ambiguity across 4 weighted dimensions after each round
+5. Gate: ambiguity ≤ 0.20 AND all dimensions meet minimums → write SPEC.md
+6. Commit SPEC.md — discuss-phase picks it up automatically on next run
+
+**Output:** `{phase_dir}/{padded_phase}-SPEC.md` — falsifiable requirements that lock "what/why" before discuss-phase handles "how"
+</objective>
+
+<execution_context>
+@~/.claude/get-shit-done/workflows/spec-phase.md
+@~/.claude/get-shit-done/templates/spec.md
+</execution_context>
+
+<runtime_note>
+**Copilot (VS Code):** Use `vscode_askquestions` wherever this workflow calls `AskUserQuestion`. They are equivalent.
+</runtime_note>
+
+<context>
+Phase number: $ARGUMENTS (required)
+
+**Flags:**
+- `--auto` — Skip interactive questions; Claude selects recommended defaults and writes SPEC.md
+- `--text` — Use plain-text numbered lists instead of TUI menus (required for `/rc` remote sessions)
+
+Context files are resolved in-workflow using `init phase-op`.
+</context>
+
+<process>
+Execute the spec-phase workflow from @~/.claude/get-shit-done/workflows/spec-phase.md end-to-end.
+
+**MANDATORY:** Read the workflow file BEFORE taking any action. The workflow contains the complete step-by-step process including the Socratic interview loop, ambiguity scoring gate, and SPEC.md generation. Do not improvise from the objective summary above.
+</process>
+
+<success_criteria>
+- Codebase scouted for current state before questioning begins
+- All 4 ambiguity dimensions scored after each interview round
+- Gate passed: ambiguity ≤ 0.20 AND all dimension minimums met
+- SPEC.md written with falsifiable requirements, explicit boundaries, and acceptance criteria
+- SPEC.md committed atomically
+- User knows they can now run /gsd-discuss-phase which will load SPEC.md automatically
+</success_criteria>