feat(harmonyos): improve remote chat interaction parity

[wgqqqqq]

Summary

• refine HarmonyOS remote chat presentation and composer interactions, including compact input geometry, monochrome send/steer controls, timeline projection, and collapsible tool/subagent cards
• keep mid-turn steering distinct from starting a new turn and preserve streamed/final assistant results across refresh and reconnect
• add remote plan projection and Build Plan support with capability negotiation, workspace-safe plan paths, and mobile plan actions
• extend Remote Connect contracts and focused coverage without changing the relay server protocol transport

Verification

• pnpm run harmony:architecture
• HarmonyOS assembleHap: passed
• HarmonyOS LocalTest: passed
• cargo test -p bitfun-services-integrations --no-default-features --features remote-connect --test remote_connect_contracts: 62 passed
• cargo test -p bitfun-core --no-default-features --features remote-connect service::remote_connect::remote_server::tests: 10 passed
• git diff --check: passed

Remote scenarios

• Remote control: exercised through Remote Connect contract/core tests and HarmonyOS emulator smoke testing
• Remote workspace: plan path validation remains constrained to the selected workspace
• Peer Device Mode and Detached Dispatch: unchanged

Known upstream check

pnpm run theme:color-audit:all still fails in existing upstream desktop/MiniApp generated appearance projections (color.surface.chrome type and --bf-color-surface-tertiary mapping). The native HarmonyOS color audit itself passes, and this PR does not modify the failing owner files.

[wgqqqqq]

Added commit 4a0dd2e to fix authoritative remote transcript snapshots being skipped when message ids and count were unchanged. Full history and message_snapshot now replace the cache; additive poll results retain the append path. The remote-chat RDB schema was bumped so affected stale transcripts rebuild once. Verified with HarmonyOS architecture checks, LocalTest, HAP build, and a Mate X7 restart test: the 34-message session restored from RDB with the final assistant body still present (703 chars).