fix(discuss): add structuredQuestionsAvailable conditional to all gates

The depth verification gate and multi-milestone readiness gate
unconditionally referenced ask_user_questions. On transports where
structuredQuestionsAvailable is false, this would trap the flow in
re-ask loops.

Add {{structuredQuestionsAvailable}} conditionals to:
- Depth verification (true: ask_user_questions, false: plain text)
- Multi-milestone Phase 3 readiness gate
- Per-milestone technical assumption verification

src/resources/extensions/gsd/prompts/discuss.md

@@ -120,19 +120,21 @@ Before moving to the wrap-up gate, present a structured depth summary as a check
 
 **Print the summary as normal chat text first** — this is where the formatting renders properly. Structure the summary across the depth checklist dimensions using the user's own terminology and framing. Cover: what you understood them to be building, what shaped your understanding most (their emphasis, constraints, concerns), and any areas where you're least confident in your understanding.
 
-**Then** use `ask_user_questions` with a short confirmation question — NOT the summary itself. The question field is designed for single sentences, not multi-paragraph summaries.
+**Then confirm:**
 
-**Convention:** The question ID must contain `depth_verification` (e.g., `depth_verification_confirm`). This naming convention enables downstream mechanical detection of this step.
+**If `{{structuredQuestionsAvailable}}` is `true`:** use `ask_user_questions` with:
+- header: "Depth Check"
+- question: "Did I capture the depth right?"
+- options: "Yes, you got it (Recommended)", "Not quite — let me clarify"
+- **The question ID must contain `depth_verification`** (e.g., `depth_verification_confirm`) — this naming convention enables downstream mechanical detection and the write-gate.
 
-Example flow:
-1. Print in chat: the full depth summary with markdown formatting (headers, bold, bullets)
-2. Call `ask_user_questions` with: header "Depth Check", question "Did I capture the depth right?", options "Yes, you got it (Recommended)" and "Not quite — let me clarify"
+**If `{{structuredQuestionsAvailable}}` is `false`:** ask in plain text: "Did I capture that correctly? If not, tell me what I missed." Wait for explicit confirmation before proceeding. **The same non-bypassable gate applies to the plain-text path** — if the user does not respond, gives an ambiguous answer, or does not explicitly confirm, you MUST re-ask. Never rationalize past a missing confirmation.
 
 If they clarify, absorb the correction and re-verify.
 
 The depth verification is the required write-gate. Do **not** add another meta "ready to proceed?" checkpoint immediately after it unless there is still material ambiguity.
 
-**CRITICAL — Non-bypassable gate:** The system mechanically blocks CONTEXT.md writes until the user selects the "(Recommended)" option. If the user declines, cancels, or the tool fails, you MUST re-ask — never rationalize past the block ("tool not responding, I'll proceed" is forbidden). The gate exists to protect the user's work; treat a block as an instruction, not an obstacle to work around.
+**CRITICAL — Non-bypassable gate:** The system mechanically blocks CONTEXT.md writes until the user selects the "(Recommended)" option (structured path) or explicitly confirms (plain-text path). If the user declines, cancels, does not respond, or the tool fails, you MUST re-ask — never rationalize past the block ("tool not responding, I'll proceed" is forbidden). The gate exists to protect the user's work; treat a block as an instruction, not an obstacle to work around.
 
 ## Wrap-up Gate
 
@@ -260,7 +262,7 @@ If a milestone has no dependencies, omit the frontmatter. The dependency chain f
 
 #### Phase 3: Sequential readiness gate for remaining milestones
 
-For each remaining milestone **one at a time, in sequence**, decide the most likely readiness mode from the evidence you already have, then use `ask_user_questions` to let the user correct that recommendation. **Non-bypassable:** If `ask_user_questions` fails, errors, returns no response, or the user's response does not match a provided option, you MUST re-ask — never rationalize past the block or auto-select a readiness mode. Present three options:
+For each remaining milestone **one at a time, in sequence**, decide the most likely readiness mode from the evidence you already have, then present the three options below to the user. **If `{{structuredQuestionsAvailable}}` is `true`:** use `ask_user_questions`. **If `{{structuredQuestionsAvailable}}` is `false`:** present the options as a plain-text numbered list and ask the user to type their choice. **Non-bypassable:** If the user does not respond, gives an ambiguous answer, or the tool fails, you MUST re-ask — never rationalize past the block or auto-select a readiness mode. Present three options:
 
 - **"Discuss now"** — The user wants to conduct a focused discussion for this milestone in the current session, while the context from the broader discussion is still fresh. Proceed with a focused discussion for this milestone (reflection → investigation → questioning → depth verification). When the discussion concludes, write a full `CONTEXT.md`. Then move to the gate for the next milestone.
 - **"Write draft for later"** — This milestone has seed material from the current conversation but needs its own dedicated discussion in a future session. Write a `CONTEXT-DRAFT.md` capturing the seed material (what was discussed, key ideas, provisional scope, open questions). Mark it clearly as a draft, not a finalized context. **What happens downstream:** When auto-mode reaches this milestone, it pauses and notifies the user: "M00x has draft context — needs discussion. Run /gsd." The `/gsd` wizard shows a "Discuss from draft" option that seeds the new discussion with this draft, so nothing from the current conversation is lost. After the dedicated discussion produces a full CONTEXT.md, the draft file is automatically deleted.
@@ -272,9 +274,9 @@ Before writing each milestone's CONTEXT.md (whether primary or secondary), you M
 
 1. **Read the actual code** for every file or module you reference. Confirm APIs exist, check what functions actually do, identify phantom capabilities (code that exists but isn't wired up).
 2. **Check for stale assumptions** — the codebase changes. Verify referenced modules still work as described.
-3. **Present findings** — use `ask_user_questions` with a question ID containing BOTH `depth_verification` AND the milestone ID (e.g., `depth_verification_M002`). Present: what you're about to write, key technical findings from investigation, risks the code review surfaced.
+3. **Present findings** — **If `{{structuredQuestionsAvailable}}` is `true`:** use `ask_user_questions` with a question ID containing BOTH `depth_verification` AND the milestone ID (e.g., `depth_verification_M002`). Present: what you're about to write, key technical findings from investigation, risks the code review surfaced. **If `{{structuredQuestionsAvailable}}` is `false`:** present the same findings in plain text and ask for explicit confirmation before proceeding.
 
-**The system mechanically blocks CONTEXT.md writes until the per-milestone depth verification passes.** Each milestone needs its own verification — one global verification does not unlock all milestones.
+**The system mechanically blocks CONTEXT.md writes until the per-milestone depth verification passes** (structured path: user selects "(Recommended)" option; plain-text path: user explicitly confirms). Each milestone needs its own verification — one global verification does not unlock all milestones.
 
 **Why sequential, not batch:** After writing the primary milestone's context and roadmap, the agent still has context window capacity. Asking one milestone at a time lets the user decide per-milestone whether to invest that remaining capacity in a focused discussion now, or defer to a future session. A batch question ("Ready/Draft/Queue for M002, M003, M004?") forces the user to decide everything upfront without knowing how much session capacity remains.