Add Overworld tile search command and enhance related documentation

- Implemented `overworld-find-tile` command in the agent for searching tiles by ID.
- Updated `README.md` and `AGENT-ROADMAP.md` to reflect new command and usage.
- Enhanced `overworld_inspect` module with tile matching functionality.

docs/z3ed/README.md

@@ -54,6 +54,9 @@ z3ed agent resource-list --type dungeon --format json
 
 # Dump sprite placements for a dungeon room
 z3ed agent dungeon-list-sprites --room 0x012
+
+# Search overworld maps for a tile ID using shared agent tooling
+z3ed agent overworld-find-tile --tile 0x02E --map 0x05
 ```
 
 ### GUI Testing Commands
@@ -201,6 +204,9 @@ z3ed overworld find-tile --tile 0x02E --format json
 
 # Narrow search to Light World map 0x05
 z3ed overworld find-tile --tile 0x02E --map 0x05
+
+# Ask the agent to perform the same lookup (returns JSON by default)
+z3ed agent overworld-find-tile --tile 0x02E --map 0x05
 ```
 
 ### Label-Aware Dungeon Edit