docs: fix ROADMAP.md references to lowercase roadmap.md

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: baijum

.claude/settings.json

@@ -6,7 +6,7 @@
         "hooks": [
           {
             "type": "command",
-            "command": "filepath=\"$TOOL_INPUT_file_path\"; case \"$filepath\" in */docs/*) echo '[Hook] Editing a docs/ file — check cross-references between spec.md, ecosystem.md, governance.md, ROADMAP.md, server-contract.md, and self-hosting.md' ;; esac; exit 0"
+            "command": "filepath=\"$TOOL_INPUT_file_path\"; case \"$filepath\" in */docs/*) echo '[Hook] Editing a docs/ file — check cross-references between spec.md, ecosystem.md, governance.md, roadmap.md, server-contract.md, and self-hosting.md' ;; esac; exit 0"
           }
         ]
       }

docs/ecosystem.md

@@ -14,7 +14,7 @@ towlion/
   starter-app          # Created from app-template
 ```
 
-Planned application repos (e.g., `uku-companion`, `fretboard-trainer`, `chord-transposer`, `practice-timer`) are tracked in the [roadmap](ROADMAP.md) under Phase 7.
+Planned application repos (e.g., `uku-companion`, `fretboard-trainer`, `chord-transposer`, `practice-timer`) are tracked in the [roadmap](roadmap.md) under Phase 7.
 
 ## Repository Types