feat: Cargo target GC, relay BuildKit cache, and sync quota relief

.dockerignore

@@ -12,3 +12,7 @@
 !src/crates/services/relay-service/Cargo.toml
 !src/crates/services/relay-service/src/
 !src/crates/services/relay-service/src/**
+!src/crates/services/page-function-runtime/
+!src/crates/services/page-function-runtime/Cargo.toml
+!src/crates/services/page-function-runtime/src/
+!src/crates/services/page-function-runtime/src/**

docs/superpowers/plans/2026-07-22-cargo-target-latest-only-gc.md

@@ -0,0 +1,39 @@
+# Cargo Target Latest-Only GC Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** On desktop:dev exit and desktop:build end, prune Cargo target caches so only the latest useful artifacts remain for the active profile.
+
+**Architecture:** A shared Node module `scripts/cargo-target-gc.mjs` owns prune logic and CLI. `scripts/dev.cjs` and `scripts/desktop-tauri-build.mjs` call it best-effort after the session/build ends.
+
+**Tech Stack:** Node.js (`node:test`, `fs`, `path`, `child_process`)
+
+## File map
+
+| File | Responsibility |
+|---|---|
+| `scripts/cargo-target-gc.mjs` | Prune incremental / fingerprint / deps; CLI + exported API |
+| `scripts/cargo-target-gc.test.mjs` | Fixture tests for keep-latest rules |
+| `scripts/dev.cjs` | Call GC after desktop / preview exit |
+| `scripts/desktop-tauri-build.mjs` | Call GC after tauri build |
+| `package.json` | `target:gc` script |
+| `src/apps/desktop/AGENTS.md` (+ CN) | One short note on GC behavior |
+
+## Tasks
+
+### Task 1: Core GC module + tests
+
+- [x] Write failing tests for incremental keep-latest and fingerprint/deps orphan cleanup
+- [x] Implement `scripts/cargo-target-gc.mjs`
+- [x] Pass `node --test scripts/cargo-target-gc.test.mjs`
+
+### Task 2: Wire desktop entrypoints
+
+- [x] Hook `dev.cjs` desktop + preview shutdown/`finally`
+- [x] Hook `desktop-tauri-build.mjs` after build
+- [x] Add `pnpm run target:gc`
+
+### Task 3: Docs + verify
+
+- [x] Brief AGENTS note
+- [x] Re-run unit tests; dry-run against real target if present

docs/superpowers/specs/2026-07-22-cargo-target-latest-only-gc-design.md

@@ -0,0 +1,56 @@
+# Cargo Target Latest-Only GC
+
+**Date:** 2026-07-22  
+**Status:** Approved (timing: exit of `desktop:dev` / end of `desktop:build`)
+
+## Problem
+
+`target/debug` grows without bound across `pnpm run desktop:dev` / build sessions (observed ~139GB). Growth is dominated by:
+
+1. Multiple `incremental/<crate>-<hash>/` roots for the same crate (rustc only GCs sessions *inside* one hash root).
+2. Stale `.fingerprint` / `deps` artifacts left after feature or unit-graph changes.
+
+## Goal
+
+After a desktop dev session exits or a desktop build finishes, keep only the latest *useful* cache for the active profile so disk usage stops ratcheting upward, without `cargo clean` and without disabling incremental compilation.
+
+## Non-goals
+
+- Changing default `profile.dev` debuginfo (optional later).
+- GC on every incremental rebuild during a live `tauri dev` session.
+- Guaranteeing a single hash per third-party crate when Cargo legitimately needs two units (lib vs build-dep).
+
+## Design
+
+### Trigger (option B)
+
+| Entry | When GC runs |
+|---|---|
+| `pnpm run desktop:dev` | After `tauri dev` exits (including Ctrl+C), in a `finally` path |
+| `pnpm run desktop:preview:debug` | On preview shutdown |
+| `pnpm run desktop:build*` (`scripts/desktop-tauri-build.mjs`) | After `tauri build` returns (success or fail; GC is best-effort) |
+| `pnpm run target:gc` | Manual |
+
+Skip GC when `BITFUN_TARGET_GC=0`. Dry-run when `BITFUN_TARGET_GC_DRY_RUN=1`.
+
+Skip when another `cargo` / `rustc` process still appears active (avoid deleting in-use artifacts).
+
+### What is pruned
+
+For `target/<triple?>/<profile>/` (default host triple omitted; profile `debug` for dev, build profile from argv):
+
+1. **incremental** — group directories by crate prefix (name before final `-`); keep the newest mtime; delete older roots. Inside a kept root, keep the newest finalized `s-*` session when multiple remain.
+2. **.fingerprint** — group by package stem; keep newest **1** for `bitfun_*` / workspace-app stems, newest **2** for other packages (build-dep dual units). Delete older groups.
+3. **deps** — delete artifacts whose trailing hash no longer appears in any remaining fingerprint directory name. Do not delete by “crate name latest only” (unsafe for dual feature units).
+
+### Safety
+
+- Never delete the profile root or final binaries by name (`bitfun-desktop`, `.app`, etc.) except via normal cargo replacement.
+- GC failures must not fail the user command (log and continue).
+- No dependency on `cargo-sweep` (macOS atime is unreliable).
+
+## Verification
+
+- Unit tests for grouping / keep-latest / deps orphan deletion on a temp fixture.
+- `node --test scripts/cargo-target-gc.test.mjs`
+- Manual: run GC dry-run against real `target/debug`, confirm incremental crate counts drop to 1 per prefix without requiring a full clean rebuild afterward for desktop:dev.

package.json

@@ -53,6 +53,7 @@
     "desktop:dev": "node scripts/dev.cjs desktop",
     "desktop:preview:debug": "node scripts/dev.cjs desktop-preview",
     "desktop:dev:raw": "cross-env-shell CI=true \"cd src/apps/desktop && tauri dev\"",
+    "target:gc": "node scripts/cargo-target-gc.mjs",
     "desktop:build": "node scripts/desktop-tauri-build.mjs",
     "desktop:build:fast": "node scripts/desktop-tauri-build.mjs --debug --no-bundle",
     "desktop:build:release-fast": "node scripts/desktop-tauri-build.mjs --no-bundle -- --profile release-fast --features devtools",