Rename depth setting — "quick/comprehensive" implies investigation thoroughness, not phase granularity

[patrick833]

Problem or motivation

Summary

The depth setting (quick / standard / comprehensive) suggests that choosing
quick results in shallower investigation, when in reality it only controls how many
phases the roadmap is sliced into. Each phase still receives the full research → plan →
check → execute → verify cycle regardless of the depth value.

Current behavior

depth	Phases	Implication from name
quick	3-5	"Less thorough"
standard	5-8	"Normal thoroughness"
comprehensive	8-12	"More thorough investigation"

A user choosing quick might expect faster but shallower analysis. A user choosing
comprehensive might expect deeper per-phase research. Neither is true — the per-phase
pipeline is identical across all three values.

What it actually controls

The number of phases in the roadmap, which determines:

• Granularity of control — more phases = more checkpoints to course-correct
• Scope per phase — fewer phases = each phase covers broader ground
• Total wall-clock time and token cost — scales linearly with phase count

Proposed solution

Proposal

Rename the setting and its values to reflect what they actually control:

Option	Current name	Suggested name
Setting	depth	granularity
Value 1	quick	coarse
Value 2	standard	standard
Value 3	comprehensive	fine

Alternative value names: broad / standard / detailed, or few / standard / many.

The setting description in /gsd:settings should also be updated from
"Planning thoroughness" to something like "Phase granularity — how finely scope is sliced."

Impact

• config.json schema change (with backward compat for existing configs)
• /gsd:settings UI text
• /gsd:new-project prompts
• User guide documentation

Alternatives considered

No response

Additional context

No response