Align dependabot with Sea Haven conventions (#39)

Switch all ecosystems to a weekly schedule and drop the redundant
patterns: ["*"] selectors. Remove the major group so patch+minor bumps
stay grouped into one PR per ecosystem while each major lands as its own
PR, matching the org standard.

Add npm coverage for the JS/TS surface (root, /infra CDK, /tests/e2e
Playwright, /ui dashboard) and assign updates to amoussa1229. Delete the
stale ui/yarn.lock so Dependabot tracks ui/bun.lock cleanly.

Refs: #34

Co-authored-by: seahaven-openswe[bot] <296972425+seahaven-openswe[bot]@users.noreply.github.com>

.github/dependabot.yml

@@ -1,52 +1,45 @@
 version: 2
 updates:
+  # Python — uv (open-swe-specific; siblings use pip)
   - package-ecosystem: "uv"
     directory: "/"
     schedule:
-      interval: "monthly"
+      interval: "weekly"
+    assignees: ["amoussa1229"]
     groups:
       minor-and-patch:
-        patterns:
-          - "*"
-        update-types:
-          - "minor"
-          - "patch"
-      major:
-        patterns:
-          - "*"
-        update-types:
-          - "major"
+        update-types: ["minor", "patch"]
 
+  # JavaScript/TypeScript — CDK (/infra), Playwright (/tests/e2e), dashboard (/ui), root tooling
+  - package-ecosystem: "npm"
+    directories:
+      - "/"
+      - "/infra"
+      - "/tests/e2e"
+      - "/ui"
+    schedule:
+      interval: "weekly"
+    assignees: ["amoussa1229"]
+    groups:
+      minor-and-patch:
+        update-types: ["minor", "patch"]
+
+  # Docker — root Dockerfile
   - package-ecosystem: "docker"
     directory: "/"
     schedule:
-      interval: "monthly"
+      interval: "weekly"
+    assignees: ["amoussa1229"]
     groups:
       minor-and-patch:
-        patterns:
-          - "*"
-        update-types:
-          - "minor"
-          - "patch"
-      major:
-        patterns:
-          - "*"
-        update-types:
-          - "major"
+        update-types: ["minor", "patch"]
 
+  # GitHub Actions
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:
-      interval: "monthly"
+      interval: "weekly"
+    assignees: ["amoussa1229"]
     groups:
       minor-and-patch:
-        patterns:
-          - "*"
-        update-types:
-          - "minor"
-          - "patch"
-      major:
-        patterns:
-          - "*"
-        update-types:
-          - "major"
+        update-types: ["minor", "patch"]