fix: remove premature research likelihood predictions from roadmap

Research decisions made at roadmap creation time are:
- Premature: Can't know if research is needed before discuss-phase
- Redundant: --skip-research flag exists for explicit control
- Counterproductive: Gives Claude an excuse to skip research entirely

Removed:
- Research: Likely/Unlikely fields from roadmap template
- detect_research_needs step from create-roadmap workflow
- "If roadmap flagged Research: Likely" checks from gsd-planner

Research now always runs during plan-phase unless:
- RESEARCH.md already exists (silent reuse)
- --skip-research flag passed
- --gaps flag passed (gap closure mode)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

agents/gsd-planner.md

@@ -112,8 +112,6 @@ Discovery is MANDATORY unless you can prove current context exists.
 - Level 2+: New library not in package.json, external API, "choose/select/evaluate" in description
 - Level 3: "architecture/design/system", multiple external services, data modeling, auth design
 
-If roadmap flagged "Research: Likely", Level 0 (skip) is not available.
-
 For niche domains (3D, games, audio, shaders, ML), suggest `/gsd:research-phase` before plan-phase.
 
 </discovery_levels>
@@ -1029,8 +1027,6 @@ Read any existing PLAN.md or DISCOVERY.md in the phase directory.
 
 <step name="mandatory_discovery">
 Apply discovery level protocol (see discovery_levels section).
-
-If roadmap flagged "Research: Likely", Level 0 (skip) is not available.
 </step>
 
 <step name="read_project_history">