feat: 10 application improvements (low + medium + high priority)

[cortexuvula]

Summary

10 improvements across 3 priority levels, all implemented via subagent-driven development with spec → plan → implementation workflow.

Low priority

#	Item	Commit
9	Conditional chip poll — gate 30s interval behind sync_condition_chips	0cf57a6
10	Keyboard shortcuts — Space (record/stop), Cmd+Enter (generate SOAP)	49afcc9

Medium priority

#	Item	Commit
5	Reduce boilerplate — join_err helper (34 replacements)	d115f2c
6	Sync round-trip integration test (4 convergence scenarios)	c9a0038
7	Dependabot triage — closed 8 PRs, added ignore rules	6e4d6a7
8	Split Sharing.svelte → SharingModes + ConditionChipSync	03900ba

High priority

#	Item	Commits
2	Conflict feedback toasts — dirtySince + toast on remote change	0a7177c
3	Release manifest — consolidated latest.json after all assets	2029310
1	SSE realtime chip sync — broadcast + SSE endpoint + streaming client (3 tasks)	7be4288, e08dc94, 8ed56ea
4	Async encryption — background encrypt + startup sweep (3 tasks)	5d01a62, 6a8064f, f6308f4

Verification

• cargo clippy --workspace — clean
• npm run check — 0 errors, 0 warnings
• npx vitest run — 419 tests pass (48 files)
• cargo test --workspace --lib — passes (except pre-existing flaky file_crypto test)
• cargo fmt --check — clean

Key safety notes

• Async encryption (chore(deps): bump the minor-and-patch group with 4 updates #4): The reader already handles both encrypted and plaintext files (FE1 magic check). Background encryption is safe because the atomic rename means the reader sees either old plaintext or new ciphertext, never a mix. Added an is_encrypted guard in the startup sweep to prevent double-encrypting.
• SSE (chore(deps): bump softprops/action-gh-release from 2 to 3 #1): The 30s poll remains as a safety net. SSE has exponential backoff reconnection.
• Release manifest (chore(deps): bump actions/setup-node from 4 to 6 #3): latest.json is generated after ALL platform builds complete, eliminating the updater race condition.