perf(commands): cache script command icon data

[JustYannicc]

What changed

• Added a module-level file icon data URL cache for script commands, keyed by resolved absolute icon path plus the icon file size and mtime signature.
• Kept script command discovery invalidation focused on script metadata while reusing unchanged file icon data across cold discoveries.
• Extended the script command discovery benchmark with an icon-heavy fixture and invalidated discovery/execution measurements.
• Added focused coverage that verifies cached file icons avoid repeat byte reads and changed icon files refresh.

Why

Running a script command after the 12s discovery TTL can force a cold rediscovery. File-based script icons were re-read and base64 encoded on every cold discovery, so icon-heavy command sets repeatedly paid the full icon I/O cost even when icon files had not changed.

Compatibility impact

• Emoji icons and https:// icon values still bypass file icon reads.
• File icon support remains limited to the existing SVG, PNG, JPG, and JPEG data URL behavior.
• Raycast metadata parsing and iconDark/icon precedence are unchanged.
• Script metadata is still refreshed on discovery cache invalidation; changed file icons are picked up when their file signature changes.

How tested

• node --test scripts/test-script-command-runner.mjs
• node --test 'scripts/test-*.mjs' (236 pass, 1 skipped)
• ./node_modules/.bin/tsc -p tsconfig.main.json --noEmit
• Codex LSP diagnostics for src/main/script-command-runner.ts: no diagnostics found
• node scripts/bench-script-command-discovery.mjs

Performance evidence

Command: SUPERCMD_BENCH_SCRIPT_COUNT=250 SUPERCMD_BENCH_SCRIPT_BODY_BYTES=0 SUPERCMD_BENCH_SCRIPT_ICON_BYTES=98304 node scripts/bench-script-command-discovery.mjs

Before cache:

• initial discovery: 31.7ms, 250 readFileSync calls, 23.4 MiB icon bytes
• invalidated discovery: 28.1ms, 250 readFileSync calls, 23.4 MiB icon bytes, 23.5 MiB total runner bytes
• invalidated execution lookup: 27.4ms, 250 readFileSync calls, 23.4 MiB icon bytes, 23.5 MiB total runner bytes

After cache:

• initial discovery: 33.5ms, 250 readFileSync calls, 23.4 MiB icon bytes
• invalidated discovery: 8.5ms, 0 readFileSync calls, 0 B icon bytes, 76.1 KiB total runner bytes
• invalidated execution lookup: 11.1ms, 0 readFileSync calls, 0 B icon bytes, 76.1 KiB total runner bytes

Default emoji benchmark remains healthy: node scripts/bench-script-command-discovery.mjs reported initial discovery 11.9ms and 0 readFileSync bytes.

Stack validation

Started from codex/perf-consolidated-integration-stack / fork/codex/perf-consolidated-integration-stack at 264fb89dc5c867d6c3d77bc4b95e26e235e326ea. Implementation branch is codex/perf-script-command-icon-cache at 7405505.

Replaces

None.

[JustYannicc]

Superseded by consolidated upstream PR #573: #573. Closing this smaller PR to keep the command/file wave consolidated.