Add experimental Synergy 3 support and persist saved servers

[joihn]

Issue Adressed

Related to #47.

Synergy difference

Synergy 3.7.2 on macOS can acknowledge screen dimensions before accepting the
client, sends relative mouse deltas as signed 16-bit values, and uses Mac physical
keycodes.

Input Leaf could report a connection before an unknown-screen refusal,
reject relative motion packets, or inject the wrong physical keys.
This change
handles those cases using the existing Synergy greeting and TLS/mTLS support.

Manually added servers also disappeared after restarting the app. Favorite
addresses were persisted but were only displayed when rediscovered. The server
list now restores saved addresses and merges them with scan results.

Changes

• Complete the input handshake on DSOP, rather than CIAK; report unknown
  screens and protocol errors directly, and reject unsupported protocol majors.

• Decode signed 16-bit DMRM deltas while retaining the previously accepted
  32-bit variant.

• Map Carbon keycodes plus one to evdev for Android HID input, retaining evdev/X11
  decoding and matching key-up events when source detection changes during a chord.

• Persist manually added, used, and favorited servers; recover addresses from
  existing favorites and connection records. Empty scans no longer hide saved servers.

• Add an optional macOS Synergy setup/status helper and guide. Registration is a
  dry run by default; applying requires a stopped service and creates private
  backups with rollback on write failure. The helper targets observed Synergy
  settings schemas 17/8 and reports the exact screen name, LAN address hints, and
  server fingerprint.

• Add protocol, input, persistence, and helper regression coverage; run the
  Python helper tests in the existing CI job.

• Android instrumented smoke tests were not run locally.

manual testing

confirmed working with 2 macos tahohe macbook + pixel 10 android 17 with Shizuku

Summary by Sourcery

Add experimental Synergy 3 support while preserving server addresses across app restarts.

New Features:

• Add experimental Synergy 3.7.2 compatibility for macOS servers, including TLS/mTLS connectivity, protocol negotiation, relative mouse motion, and physical key mapping.
• Add a macOS setup and status helper for registering Android clients with Synergy settings and inspecting connection state.
• Persist manually added, used, and favorited server addresses and merge saved entries with network scan results.

Bug Fixes:

• Prevent premature successful connections when Synergy acknowledges dimensions but later rejects an unknown screen.
• Report unsupported protocol versions, unknown screens, and malformed protocol messages as explicit connection failures.
• Preserve correct key-up behavior when input encoding detection changes while keys are held.

Enhancements:

• Expand server and connection messaging to use server-agnostic terminology and expose Synergy-specific failure guidance.

CI:

• Run the Synergy setup helper's Python regression tests in CI.

Documentation:

• Document experimental Synergy 3 setup, compatibility limits, server registration, status inspection, and validation procedures.

Tests:

• Add regression coverage for Synergy handshakes, signed relative motion, keycode decoding, server persistence, list merging, and setup-helper behavior.

[sourcery-ai]

Reviewer's Guide

This PR adds experimental Synergy 3.7.2 interoperability by enforcing the post-dimension handshake, supporting signed 16-bit motion and macOS physical keycodes, while also making server addresses durable and introducing a guarded macOS setup/status helper with documentation and CI coverage.

Sequence diagram for the Synergy 3 connection handshake

sequenceDiagram
    participant App as InputLeaf
    participant Server as SynergyCore
    App->>Server: TLS/mTLS connection
    Server-->>App: Hello
    App->>Server: ClientHello
    App->>Server: QINF
    Server-->>App: DINF
    App->>Server: CIAK
    Server-->>App: CROP
    Server-->>App: DSOP
    alt Unknown screen
        Server-->>App: EUNK
        App-->>App: ConnectResult.UNKNOWN_SCREEN
    else Protocol error
        Server-->>App: BadMessage
        App-->>App: ConnectResult.PROTOCOL_ERROR
    else Accepted
        App->>App: Start readLoop
    end

Loading

Flow diagram for persistent server list merging

flowchart LR
    Saved[Saved addresses]
    Scan[Network scan results]
    Merge[mergeServerLists]
    List[Server list]
    Add[addManualServer]
    Store[saveServer]
    Add --> Store --> Saved
    Saved --> Merge
    Scan --> Merge
    Merge --> List

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File-Level Changes

Change	Details	Files
Tighten Synergy-compatible connection negotiation and packet decoding.	Require a successful DSOP before declaring the handshake complete and reject unsupported protocol majors. Surface unknown-screen and malformed-protocol failures without retrying or fallback. Decode signed 16-bit relative mouse movement while retaining 32-bit compatibility.	app/src/main/java/com/inputleaf/android/network/InputLeapConnection.kt app/src/main/java/com/inputleaf/android/network/ConnectResult.kt app/src/main/java/com/inputleaf/android/network/ConnectionTransportPolicy.kt app/src/main/java/com/inputleaf/android/protocol/ProtocolParser.kt app/src/test/java/com/inputleaf/android/network/InputLeapConnectionTest.kt app/src/test/java/com/inputleaf/android/protocol/ProtocolParserTest.kt
Add macOS physical-key translation and robust pressed-key tracking for HID injection.	Map Carbon keycodes plus Synergy’s offset to evdev and preserve existing evdev/X11 detection. Cache the physical mapping between key-down and key-up events, clearing held state on disconnect or HID detach. Add regression coverage for modifiers, navigation keys, ambiguous encodings, and non-Latin input.	app/src/main/java/com/inputleaf/android/inject/MacKeyCode.kt app/src/main/java/com/inputleaf/android/inject/ProtocolScanCodeDecoder.kt app/src/main/java/com/inputleaf/android/inject/AccessibilityInputInjector.kt app/src/main/java/com/inputleaf/android/shizuku/ShizukuInputInjector.kt app/src/test/java/com/inputleaf/android/inject/ProtocolScanCodeDecoderTest.kt
Persist server addresses independently from discovery and merge saved entries into the server list.	Store manually added, used, and favorited addresses in DataStore and recover addresses from legacy favorites, fingerprints, and transport records. Keep saved servers visible across restarts and empty scans while allowing discovered metadata to replace placeholders. Make preferences injectable for isolated persistence tests.	app/src/main/java/com/inputleaf/android/storage/AppPreferences.kt app/src/main/java/com/inputleaf/android/ui/MainViewModel.kt app/src/main/java/com/inputleaf/android/ui/ServerListScreen.kt app/src/test/java/com/inputleaf/android/storage/AppPreferencesTest.kt app/src/test/java/com/inputleaf/android/ui/ServerListPersistenceTest.kt
Provide an experimental macOS Synergy 3 registration and status workflow with safe settings updates.	Add a dry-run-by-default Python helper for schema 17/8 settings, screen registration, trust configuration, status reporting, LAN hints, and fingerprints. Require stopped Synergy processes for writes, verify files are unchanged, create private backups, use atomic writes, and restore originals on failure. Document setup, compatibility limits, operational guidance, and optional live testing.	scripts/synergy3_setup.py scripts/tests/test_synergy3_setup.py docs/synergy3-android.md README.md docs/TESTING.md
Integrate helper regression tests into CI and broaden user-facing terminology and error reporting.	Run the Python helper unit tests in the existing CI job. Update connection and fingerprint messaging to refer generically to the server and explain Synergy-specific failures.	.github/workflows/ci.yml app/src/main/java/com/inputleaf/android/ui/MainViewModel.kt app/src/main/java/com/inputleaf/android/ui/FingerprintDialog.kt app/src/main/java/com/inputleaf/android/ui/SettingsScreen.kt

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[sourcery-ai]

Hey - I've found 1 issue

Prompt for AI Agents

Please address the comments from this code review:

## Individual Comments

### Comment 1
<location path="app/src/main/java/com/inputleaf/android/inject/ProtocolScanCodeDecoder.kt" line_range="30" />
<code_context>
+    }
+
+    @Synchronized
+    fun clearPressedKeys() = pressedKeys.clear()

     fun toEvdev(button: Int, keysym: Int): Int {
</code_context>
<issue_to_address>
**issue (bug_risk):** `clearPressedKeys()` releases the pressed-key map but leaves the learned `encoding` unchanged. After disconnecting from a macOS server and connecting to an evdev or X11 server, the decoder continues applying the previous server's encoding and injects incorrect physical keys.

**Triggers:** When the same input injector instance reconnects to a server using a different keycode encoding.

**Suggested fix:** Reset `encoding` to null as part of decoder connection cleanup, or provide a separate reset method that clears both pressed keys and the learned encoding.

```suggestion
    fun clearPressedKeys() {
        pressedKeys.clear()
        encoding = null
    }
```
</issue_to_address>

---

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[sourcery-ai]

issue (bug_risk): clearPressedKeys() releases the pressed-key map but leaves the learned encoding unchanged. After disconnecting from a macOS server and connecting to an evdev or X11 server, the decoder continues applying the previous server's encoding and injects incorrect physical keys.

Triggers: When the same input injector instance reconnects to a server using a different keycode encoding.

Suggested fix: Reset encoding to null as part of decoder connection cleanup, or provide a separate reset method that clears both pressed keys and the learned encoding.

Suggested change

	fun clearPressedKeys() = pressedKeys.clear()
	fun clearPressedKeys() {
	pressedKeys.clear()
	encoding = null
	}