fix(birdhouse): invoke Rs2Walker and hardcode mushtree transport

[runsonmypc]

Summary

• TELEPORTING state was a no-op that skipped straight to DISMANTLE_HOUSE_1 without invoking Rs2Walker, so the player never left the bank. Now calls Rs2Walker.walkTo(birdhouseLocation1) which routes via digsite pendant to Fossil Island.
• MUSHROOM_TELEPORT state was also a no-op that relied on Rs2Walker to route through the mushtree, which sometimes detoured to the bank. Replaced with direct mushtree interaction: Use object → select Mushroom Meadow from widget → wait for arrival.
• Version bump 1.1.3 → 1.1.4

Test plan

• Start plugin at a bank on the mainland — verify it gears up, then Rs2Walker routes to Fossil Island via digsite pendant
• After houses 1 & 2, verify mushtree interaction fires and player arrives at Mushroom Meadow
• Complete full 4-house run end to end