Add Claude Code delegation to Maple Agent

[benthecarman]

Adds Claude Code delegation alongside Codex in Maple Agent. Tasks can stream activity, answer approval and question cards, resume delegated sessions, and stop their child processes. The native Rust transport is adapted from the pinned Goose provider and requires only the installed Claude CLI.

The Claude card uses its logo and checks claude auth status --json to show signed-in, signed-out, or unknown status. Status probes are bounded and account details are not retained. Failed launches before session confirmation retry with a fresh session instead of trying to resume an unsaved UUID. Claude's multiSelect questions support multiple choices and optional notes in Maple's question card.

For both providers, Settings controls availability in the composer. Each task must explicitly select a provider; disabling it in Settings hides it and blocks saved selections on the next run. Task choices persist across restarts.

Validation:

• The component's full just ci recipe passed on NixOS using installed host tools: formatting, four Clippy configurations, warning-denied workspace builds, 809 workspace tests, and 35 headless tests. This was not a pinned nix develop run.
• Native Rust CLI fixtures cover streaming, confirmed-session resumption and failed-start recovery, provider isolation, approvals, multiple-choice answers, cancellation, malformed output, process cleanup, and authentication probe failures/timeouts. The cancellation fixture re-executes itself as a sleeping child and needs no host sleep executable.
• Settings gates and session tool refresh tested with warm and cold runtimes and ACP exclusion.
• The native question-card fixture passed interactive Linux checks in light/dark themes: multiple selection and deselection, numbered shortcuts, notes, advancing to a single-choice question, and Vim cursor movement/Enter toggling. Runtime broker tests cover answer delivery; the visual fixture runs without authentication or inference.
• Earlier Linux debug-app checks verified the Claude logo, live sign-in status in light/dark themes, and the Settings toggle. Authenticated composer interaction was not exercised in the isolated offline UI profile.
• An earlier non-Nix Linux release build passed, and the user tested the uploaded delegation build.

Native GUI checks ran on Linux only.

The fixture log race reported in review is fixed: complete JSON records and their newlines are appended together, and the resumption test rejects malformed records directly. The affected test passed 100 consecutive local runs; the full just ci recipe passed again (844 tests). Hosted Linux/macOS confirmation is pending on this revision.

[AnthonyRonning]

Two non-blocking findings from a local review against claude 2.1.258 (stream-json protocol, interrupt, resume, and AskUserQuestion all verified outside the GUI). Details inline.

[AnthonyRonning]

The two fixups resolve both earlier comments (session confirmation before --resume, and multiSelect through to the card), thanks. Requesting changes only because the new claude_native_retries_only_resume_confirmed_sessions test fails deterministically on macOS and Ubuntu CI (Windows passes because the fixture tests are Unix-only), and I reproduced it locally on macOS 4/4 runs. It is a fixture log race, not a runtime bug; details inline.

[AnthonyRonning]

Fixture fix confirmed: claude_native_retries_only_resume_confirmed_sessions and the other six claude_native_*/detection tests pass locally on macOS at 7a9b23c (previously failed 4/4 runs). Single-write log records are the right fix and the stricter parser will catch any regression. Earlier comments on session confirmation and multiSelect are resolved. Approving; CI on this head still needs a workflow approval click.