feat(KitsunePackRelayLauncher): v0.1 scaffold + verified hook (#227)

[AdaInTheLab]

Summary

Closes #227 — the in-game half of "make every Connect button across the launcher actually one-click into the server."

Sibling mod to KitsuneJoinDiag. KitsuneJoinDiag surfaces the actual DisconnectReason when joins FAIL; this mod is the SUCCESS-path counterpart that skips the splash → main menu → Direct Connect → paste → CONNECT dance when the launcher hands off a known target.

v0.1 scope (this PR — scaffold + verified hook)

Lands a working mod that:

• Loads + attaches Harmony patches without errors. dotnet build -c Release succeeds; the type references (XUiC_MainMenu, nameof(XUiC_MainMenu.OnOpen)) resolve against the real game assemblies.
• Reads the sentinel file <userdatafolder>/packrelay-quickjoin.json on XUiC_MainMenu.OnOpen() (postfix), with a 60s freshness gate.
• Logs what it would do instead of actually firing the connect. The full UI driving is deferred to v0.2.
• Deletes the sentinel after reading (whether stale or fresh) so a re-open of the main menu mid-session and the next manual launch both stay clean.
• Session-static fired-flag so only the first OnOpen of the process checks the sentinel (player quitting from a server back to main menu won't re-fire).

Output on a sentinel hit looks like:

================================================================
[KitsunePackRelayLauncher] v0.1 stub: WOULD auto-connect now.
  host:      play.kitsuneden.net
  port:      26900
  writtenAt: 2026-05-28 19:30:00Z
  age:       2.4s

  v0.2 will fill in the UI driving here:
    1. Find XUiC_ServerBrowserDirectConnect in the XUi tree
    2. Set its txtIp + txtPort field text
    3. Fire btnDirectConnectConnect.OnPressed
================================================================

Reflection findings (the spelunk)

Used Mono.Cecil from PowerShell to enumerate Assembly-CSharp.dll. Key candidates surfaced:

• XUiC_MainMenu.OnOpen() — the hook this mod uses. Fires when the main menu becomes visible after splash dismissal.
• XUiC_ServerBrowserDirectConnect — the Direct Connect dialog. Fields visible: txtIp (XUiC_TextInput), txtPort (XUiC_TextInput), btnDirectConnectConnect (XUiC_SimpleButton), btnCancel, cancelTarget, ipPortMatcher (Regex). This is what v0.2 will drive.

Full notes in vault: D:\Claude\Claude\runbooks\packrelay-quickjoin-mod-plan.md.

What's NOT in this PR

• The actual UI driving (v0.2): set txtIp / txtPort field text + fire btnDirectConnectConnect.OnPressed. The strategy is documented in the patch's doc comment; implementing it needs careful XUi-tree-walking that's easier to debug as a focused follow-up.
• Launcher-side sentinel writer (v0.2): the PackRelay launcher's launch_game Tauri command will need to write packrelay-quickjoin.json into the active profile's userdatafolder before spawning 7DTD. Small Rust change in packrelay-launcher repo, deferred.

Safety

• Postfix is wrapped in try/catch — a malformed sentinel never breaks 7DTD's main menu open path.
• Stale-sentinel detection deletes the file so a launcher that crashed before launching 7DTD doesn't leave a time bomb for the next manual launch.
• Harmless on dedicated servers (XUiC path doesn't fire server-side), safe to ship in a both-sides pack.

Test plan

• dotnet build -c Release from src/KitsunePackRelayLauncher/ succeeds (it does — verified in this commit).
• Drop KitsunePackRelayLauncher.dll + ModInfo.xml into a 7DTD client's Mods folder.
• Launch 7DTD without a sentinel file. The main menu opens normally; the mod's init log line appears at startup; no [KitsunePackRelayLauncher] WOULD auto-connect block (because no sentinel).
• Write a sentinel file by hand: <userdatafolder>/packrelay-quickjoin.json with valid host/port/writtenAt: <now>. Launch 7DTD. After main menu appears, the WOULD auto-connect block appears in Player.log with the correct host/port. The sentinel file is gone after.
• Write a sentinel with writtenAt: 2026-05-27T00:00:00Z (yesterday). Launch 7DTD. The stale-sentinel log line appears; sentinel deleted; no WOULD auto-connect.
• Write a sentinel with malformed JSON. Launch 7DTD. The malformed-warning log line appears; sentinel deleted.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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