perf(cli): optimize JSON output across all commands

[TannerTorrey3]

Summary

• Systematically compact --format json output for 14/19 CLI commands, achieving 91.4% reduction (774KB → 67KB aggregate across all commands)
• Adds shared helpers (stripNulls, roundFloat, compactTreeNode) in format.ts and command-specific compaction functions
• Strips full UUIDs, replaces absolute paths with repo-relative paths, drops default/zero-value fields, removes empty arrays, and groups results by file where applicable

Per-command savings

Command	Before	After	Reduction
subsystems	660KB	3.4KB	99.5%
entity	30KB	2.2KB	92.7%
trace	22KB	3.5KB	84.1%
impact	18KB	2.1KB	88.3%
diff	15KB	2.8KB	81.3%
inventory	12KB	4.2KB	65.0%
map	5.4KB	1.2KB	77.8%
explain	3.8KB	1.9KB	50.0%
smells	2.8KB	1.1KB	60.7%
rank	1.4KB	0.6KB	57.1%
locate	1.2KB	0.9KB	25.0%
search	0.8KB	0.5KB	37.5%
history	0.6KB	0.3KB	50.0%
callers/read	minor	minor	path compaction

Files changed (19)

• format.ts — new shared helpers: stripNulls(), roundFloat(), compactTreeNode(), updated formatPatches()
• facts.ts — relativePath() applied to all path fields
• 14 command files — command-specific JSON compaction
• 3 command files — path compaction only

Test plan

• npm run build passes (0 errors)
• All 424 tests pass (npx vitest run)
• Validated optimized output against live backend for subsystems, entity, map, smells, explain, impact, rank, inventory, diff, history, trace, locate, search, read, callers
• Verify no downstream consumers depend on removed fields

🤖 Generated with Claude Code