feat: opencode v2 server support with v1 compatibility

[bluetoe-99]

What

Fixes #194 (Android: chat input hidden behind keyboard).
Fixes #205 (opencode2 support?).
Fixes #156 (Unable to see the input box — same composer-behind-keyboard report as #194).

Adds opencode v2 server support while keeping every opencode 1.x (≤ 1.18.x) server working. npm install -g opencode-ai still installs the 1.x line (latest = 1.18.32 as of 2026-09-25), so both APIs are common in the wild and the client now speaks whichever the server speaks.

v2 (src/lib/sdk.ts, src/lib/v2-shape.ts)

• /api/... endpoints, the v2 SSE envelope ({id, type, data}), the renamed message/part shapes, interrupt, staged revert, session diff.
• The question tool arrives as a server-side form nested under data.form on form.created. Reading it flat silently dropped every prompt, so questions never appeared in the app.
• Session-scoped permission and form replies.

v1 (src/lib/sdk-v1.ts, src/lib/api-detect.ts)

The transport main already ships, restored unchanged (sessions, prompts, abort, revert, diff, questions, permissions, agents, commands, providers, file browsing). A connect-time probe classifies the server by response content type — never status code, because unknown routes on both server generations fall through to the web SPA with 200 text/html:

probe	v2.0.16	1.18.32
GET /api/info	200 application/json, or 401 unauthenticated	200 text/html (SPA)
GET /global/health	200 text/html (SPA)	200 application/json {healthy, version}

The detected api and serverVersion are stored on the connection, reused across screens, and invalidated when the URL changes; createClient() dispatches on them.

Selection and copying

• MessageTextSheet + src/lib/message-text.ts: Select text and Edit are header buttons, and the sheet renders the whole message (text, reasoning, tool input/result/error, files) in a plain ScrollView where native selection actually works, with Copy all as the whole-message fallback. The bubble itself has no press at all: a press whose movement stays inside its bounds is kept by the touchable, which is what opened the message menu mid-scroll.
• Inline selection is now iOS-only for user message text, message error text, code lines and diff lines. selectable <Text> inside FlatList rows is react-native#46999 (still open, no linked PR) and Markdown.tsx already works around it. ToolCallCard, ReasoningBlock, ErrorBoundary and Markdown.tsx are unchanged.
• Wide code and diff lines wrap instead of scrolling sideways. CodeBlock's Copy still hands the clipboard the original string, so pasted code is byte-identical to what the server sent.
• Keyboard avoidance via react-native-keyboard-controller, including system-bar insets, so the composer is never hidden behind the keyboard (Android: chat input hidden behind keyboard #194); the SSE stream reconnects on app foreground.

Screenshots

Wrapped code block with the header buttons and the reasoning block:

Composer visible above the keyboard (#194):

Select text sheet with Copy all:

Verification

• v2: live opencode 2.0.16 server; the question path was verified by replaying a captured form.created stream.
• v1: live opencode serve on 1.18.32 — health, project, path, session create/list/update/delete/abort/messages, agents, commands, questions, permissions, providers, and the wrapped {"payload": ...} event stream through the existing unwrap in stores/events.ts.
• tsc --noEmit clean; npm test 363/363, including new suites for the probe classifier, the v2 shape translator, message-text assembly, and two component regression files.

docs/v2-api-map.md records the verified API maps, event schemas and probe behaviour for both server generations.

Notes

• New dependency: react-native-keyboard-controller (its transitive react-native-is-edge-to-edge is already in the lock).
• Behaviour change worth calling out: message actions moved from a long-press menu to header buttons, and holding a message no longer opens anything.
• I can see fix(android): prevent keyboard overlap across input screens #193, fix(android): keep composer synchronized with IME #201, fix(keyboard): restore adjustResize for edge-to-edge displays (v0.4.16) #206 and fix(android): keep IME prompts usable #208 open on the same keyboard problem. Happy to rebase onto whichever you take, or to drop the keyboard part if you'd rather keep it separate from the API work.
• Version bumps and per-version changelogs are deliberately left out — happy to follow the release process used for prior versions. android/ is untouched because CI runs expo prebuild.
• One commit; happy to split it into smaller PRs if you'd prefer.

DCO signed off.