feat(speckit): integrate ux reference into workflows

Introduce a UX reference stage to ensure technical plans align with
user experience goals. Adds a new template, a generation step in the
specification workflow, and mandatory validation checks during
planning to prevent technical compromises from degrading the defined
user experience.

.kilocode/workflows/speckit.plan.md

@@ -22,7 +22,7 @@ You **MUST** consider the user input before proceeding (if not empty).
 
 1. **Setup**: Run `.specify/scripts/bash/setup-plan.sh --json` from repo root and parse JSON for FEATURE_SPEC, IMPL_PLAN, SPECS_DIR, BRANCH. For single quotes in args like "I'm Groot", use escape syntax: e.g 'I'\''m Groot' (or double-quote if possible: "I'm Groot").
 
-2. **Load context**: Read FEATURE_SPEC, `semantic_protocol.md` and `.specify/memory/constitution.md`. Load IMPL_PLAN template (already copied).
+2. **Load context**: Read FEATURE_SPEC, `ux_reference.md`, `semantic_protocol.md` and `.specify/memory/constitution.md`. Load IMPL_PLAN template (already copied).
 
 3. **Execute plan workflow**: Follow the structure in IMPL_PLAN template to:
    - Fill Technical Context (mark unknowns as "NEEDS CLARIFICATION")
@@ -64,6 +64,10 @@ You **MUST** consider the user input before proceeding (if not empty).
 
 **Prerequisites:** `research.md` complete
 
+0. **Validate Design against UX Reference**:
+   - Check if the proposed architecture supports the latency, interactivity, and flow defined in `ux_reference.md`.
+   - **CRITICAL**: If the technical plan requires compromising the UX defined in `ux_reference.md` (e.g. "We can't do real-time validation because X"), you **MUST STOP** and warn the user. Do not proceed until resolved.
+
 1. **Extract entities from feature spec** → `data-model.md`:
    - Entity name, fields, relationships
    - Validation rules from requirements