Replace embedded Kubo (mobile.aar) with the freedom-ipfs Rust reader

[meinharrd]

Motivation

IPFS/IPNS currently comes from an embedded Kubo node: mobile.aar (built in solardev-xyz/freedom-node-mobile, gomobile) wrapped by swarmnode/src/main/java/baby/freedom/swarm/IpfsNode.kt. iOS instead embeds solardev-xyz/freedom-ipfs, a read-only Rust IPFS reader with a loopback gateway. Moving Android to freedom-ipfs:

• drops the Go runtime + full Kubo daemon (APK size, memory, battery),
• since the bee→ant swap we only use the Kubo half of mobile.aar, so this removes the freedom-node-mobile dependency entirely,
• unifies retrieval behaviour with iOS (verified blocks, delegated routing + light-DHT fallback, bounded cache),
• gains real mobile lifecycle hooks (background/foreground, low-memory, network-change) that Kubo never exposed,
• deletes the Kubo config-JSON DNS patching hack in IpfsNode.kt (ensureDnsConfigPatched) — freedom-ipfs speaks DoH natively.

Blocked on: solardev-xyz/freedom-ipfs#16 (freedom-ipfs has no Android export yet — iOS xcframework only).

Integration plan (mirrors the ant integration)

1. Vendor the native lib. Build libfreedom_ipfs_mobile.so per ABI in the freedom-ipfs repo (cargo xtask build-android-arm64 / -x86_64, per #16) → copy into swarmnode/src/main/jniLibs/{arm64-v8a,x86_64}/. Vendor freedom_ipfs.h into swarmnode/src/main/cpp/ next to ant.h.

2. JNI shim. New swarmnode/src/main/cpp/freedom_ipfs_jni.c (same pattern as ant_jni.c), added to CMakeLists.txt. Minimum surface:

• freedom_ipfs_node_new_with_data_dir / freedom_ipfs_node_free
• freedom_ipfs_node_start_gateway_online_with_config_v3 with addr = "127.0.0.1:0" (ephemeral port, same trick as today) — params: delegated router URL(s), routing mode, max concurrent requests, DHT query timeout, DHT max providers, request queue timeout
• freedom_ipfs_node_gateway_url (replaces Kubo's gatewayAddr() for IpfsInfo.gatewayUrl)
• freedom_ipfs_node_stop_gateway
• freedom_ipfs_node_diagnostics (+ retrieval_stats / routing_stats) for the status UI
• lifecycle: enter_background, enter_foreground, handle_low_memory, handle_network_change, trim_cache / clear_cache
• freedom_ipfs_version for logging
• string/buffer frees (freedom_ipfs_string_free, freedom_ipfs_buffer_free)

The native gateway request API (freedom_ipfs_gateway_request_*) is not needed — we consume the HTTP loopback gateway, as the browser already does with ant and Kubo.

3. Rewrite IpfsNode.kt, keep its public shape. Same state: StateFlow<IpfsInfo> + start()/stop()/dispose() contract so NodeService (maybeStartIpfs/maybeStopIpfs), the AIDL broadcast, and Settings UI stay untouched. Changes inside:

• construct node with dataDir = filesDir/ipfs-reader (new dir; delete the old Kubo repo at filesDir/ipfs on first successful start — it's just a cache + keys, nothing user-owned)
• delete ensureDnsConfigPatched and the offline-init dance
• peer count: freedom-ipfs has no connectedPeerCount. Repoll diagnostics instead and surface cache hits / provider blocks / bitswap blocks (or drop the peers row from the IPFS status card). Touches IpfsInfo.kt / Settings status UI.

4. Settings mapping (NodeSettings.kt, Settings screen):

• ipfs_routing_mode (Kubo "autoclient"/"dht") → freedom-ipfs routing-mode enum (auto / delegated-only / light-DHT / offline). Pick new default = auto; migrate stored values.
• ipfs_low_power (Kubo lowpower profile) has no direct equivalent → either drop the toggle or map it to conservative config-v3 values (lower max concurrent requests / DHT fanout / shorter timeouts).
• Bonus over Kubo: config changes can apply via restart_gateway_online_with_config_v3 instead of requiring an off/on cycle.

5. Wire the lifecycle hooks (new capability, do it in this pass): handle_network_change from a ConnectivityManager callback in NodeService, handle_low_memory/trim_cache from onTrimMemory, background/foreground from the service's foreground state.

6. Verify ENS/DNSLink .eth coverage. The Kubo integration patched eth. → https://dns.eth.limo/dns-query for .eth DNSLink. freedom-ipfs defaults to Cloudflare DoH for DNSLink; confirm the in-app EnsResolver path covers all ens:// flows, otherwise we need per-TLD resolver config upstream (would extend #16).

7. Cleanup. Delete swarmnode/libs/mobile.aar + its Gradle dep, drop the gomobile classes from consumer-rules.pro if referenced, update README build recipe (freedom-node-mobile section → freedom-ipfs section).

Testing

• ipfs://<cid> file + directory (index.html fallback, listing) on emulator (x86_64) and arm64 device
• ipns://<key> and DNSLink (ipns://en.wikipedia-on-ipfs.org)
• ens:// site that resolves to an IPFS contenthash
• Range requests (seek in a video) — gateway supports bounded streaming + Content-Range
• Toggle off/on in Settings; kill :node process and restart; airplane-mode → network-change recovery
• Error pages for bad CIDs / unreachable content still render via ErrorPage.kt
• APK size and idle battery before/after (expect both to improve)

[meinharrd]

Proof-of-concept on branch freedom-ipfs-trial, using .sos built from solardev-xyz/freedom-ipfs#17: JNI shim + rewritten IpfsNode.kt (same StateFlow surface, NodeService untouched). Verified on the x86_64 emulator against the public network: ipfs://<cid> file retrieval (gateway up in ~270 ms, HTTP 200) and ipns://ipfs.tech DNSLink site rendering end-to-end. Notes for the real change: connectedPeers now carries verified-blocks-fetched (no peer set in the reader), bare-CID single files are served as application/octet-stream and render blank in WebView (Kubo sniffed text — consider handling), and mobile.aar is still bundled in the trial (removal is this ticket's cleanup step; per-ABI debug APK is 236 MB with both stacks).

[meinharrd]

Merged to main (990080b..a3c9ad3): embedded Kubo replaced by the freedom-ipfs reader (JNI shim over libfreedom_ipfs_mobile.so from solardev-xyz/freedom-ipfs#16), mobile.aar dropped, plus R8 minification for release builds.

One fix was needed on top of the trial: freedom-ipfs serves bare /ipfs/<cid> with 200 where Kubo 301-redirected to the trailing-slash form, so sites using relative asset paths (e.g. vitalik.eth) rendered unstyled. a3c9ad3 normalizes bare roots to /ipfs/<cid>/ client-side; the gateway ignores the slash on single-file CIDs so it's safe for non-directory roots.

Verified on the x86_64 emulator against the public network: ipns://ipfs.tech and ens://vitalik.eth render fully styled through freedom-ipfs, ens://swarm.eth (ant) unaffected; unit tests green (one pre-existing timing-flaky GatewayProbe test unrelated to this change).

Still open from the trial notes: bare-CID single files served as application/octet-stream render blank in the WebView (Kubo sniffed text).