feat: make learnings search limits configurable via gstack-config

[MrAladdin]

Summary

• Add learnings_preamble_limit and learnings_skill_limit config keys to gstack-config
• Preamble and skill-internal learnings searches now read limits dynamically from ~/.gstack/config.yaml instead of using hardcoded values (3 and 10)
• Users with large-context models (200K+) can increase limits to load more project memory per session

Motivation

The hardcoded --limit 3 (preamble) and --limit 10 (skill) were designed for the lowest-common-denominator model context window. Users running Claude Opus, GPT-4.5, or other large-context models have ample room to load 20-30 learnings without meaningful token pressure (~2000 tokens for 20 entries). Making this configurable lets power users get more value from accumulated project memory.

Changes

File	Change
bin/gstack-config	Add learnings_preamble_limit (default: 3) and learnings_skill_limit (default: 10) to defaults table, header comments, and list/defaults enumeration
scripts/resolvers/preamble/generate-preamble-bash.ts	Replace --limit 3 with dynamic $(gstack-config get learnings_preamble_limit)
scripts/resolvers/learnings.ts	Replace --limit 10 with dynamic $(gstack-config get learnings_skill_limit)
test/gen-skill-docs.test.ts	Update assertion from literal --limit 3 to --limit "$_LEARN_PREAMBLE_LIMIT"
*/SKILL.md	Regenerated (no template changes)

Usage

# Increase preamble learnings (loaded every skill start)
gstack-config set learnings_preamble_limit 20

# Increase skill-internal learnings search
gstack-config set learnings_skill_limit 30

# Check current values
gstack-config defaults | grep learnings

Backwards compatibility

• Default values match the previous hardcoded behavior (3 and 10)
• Users who never set these keys see zero behavior change
• One extra gstack-config get call per preamble (~5ms, same as existing config reads)

Test plan

• bun test test/gen-skill-docs.test.ts — 385 pass, 0 fail
• bun test browse/test/gstack-config.test.ts — 17 pass, 3 fail (pre-existing, unrelated)
• gstack-config get/set/list/defaults all display new keys correctly
• Generated SKILL.md files contain dynamic limit variable
• --host hermes generation produces correct $GSTACK_BIN/gstack-config get calls

🤖 Generated with Claude Code