Optimize the skill + extract resolve-session to CLI

[narghev]

Summary

Two phases of work, two commits:

Phase 1 — 07b78a4 Simplify the skill: ~30% prose reduction on both askdiff/SKILL.md and askdiff-dev/SKILL.md (Steps 1–4 kept in sync). No behavior change. Drops dead branches (e.g. the (none …) troubleshooting paragraph for a code path that now throws), collapses 13-line footgun blocks into 3-line inline notes, removes "tell the user" enumerations that just restate what's already in the bash output.

Phase 2 — f18342c Extract keyword session search to resolve-session CLI subcommand: moves Step 4c's inline mktemp/find/grep -cFf bash into a typed CLI subcommand (packages/cli/src/resolve-session.ts), keeping the public-facing skill behavior identical but making the search testable and shell-safe.

Bugs found and fixed during testing

• Commander v14 --cwd overlap: parent and subcommand both declared -c, --cwd, so commander silently routed the flag to the parent — the subcommand always saw process.cwd(). Read from program.opts() instead.
• Step 4b prefix-glob in zsh: existing skill bash used shopt -s nullglob (bash-only) and ${matches[0]} (zsh is 1-indexed, so empty). Replaced with find + while read + for "${matches[@]}" — works in both shells.
• Dev-skill tsx invocation: the CLI's static import { PROTOCOL_VERSION } from "@askdiff/protocol" failed under ESM because the protocol package is CJS. Lazy-loaded inside runServer so resolve-session never triggers protocol load.
• Skill prose regression: I had said "pass --diff-file only for description-based diffs" — original bash always extracted paths. Reverted to "always pass; omit --sha/--branch for working-tree."

Test plan

• pnpm lint clean
• pnpm test 111 passing (was 89; +17 unit, +5 integration including a tsx-path regression guard)
• pnpm run build clean (CLI bundle 32K, skill.md with both ASKDIFF_VERSION lines pinned)
• Smoke tests against real ~/.claude-personal/projects/<this>/*.jsonl for 9 flag combinations
• Edge cases on tmpdir fixtures: missing dir, empty needles, special chars in keywords
• Built CLI: node packages/cli/dist/index.js resolve-session … works
• Dev path: pnpm --filter askdiff exec tsx src/index.ts resolve-session … works
• Walked 9 natural-language inputs through Steps 1–4 manually (working tree, last commit, branch comparison, vague description w/ commit-ladder, explicit prefix in zsh after fix, full UUID, keyword + working-tree, etc.)
• End-to-end skill invocation is intentionally not run from this branch (would open a browser tab); reviewer can validate by running /askdiff and /askdiff-dev after merge.

Stats

	before	after
askdiff/SKILL.md	493 lines	406 lines (-18%)
askdiff-dev/SKILL.md	496 lines	425 lines (-14%)
tests	89	111
50-line mktemp/find/grep bash	inline	extracted to resolve-session.ts

Suggested release

v0.4.0 (minor) — adds public CLI subcommand resolve-session, includes two user-facing bug fixes for the /askdiff session <prefix> and /askdiff-dev keyword-search paths.

🤖 Generated with Claude Code