feat: add snapshot size limits and optional snapshots to fix token overflow

Implements comprehensive solution for browser_click and other interactive tools
returning massive responses (37K+ tokens) due to full page snapshots.

Features implemented:
1. **Snapshot size limits** (--max-snapshot-tokens, default 10k)
   - Automatically truncates large snapshots with helpful messages
   - Preserves essential info (URL, title, errors) when truncating
   - Shows exact token counts and configuration suggestions

2. **Optional snapshots** (--no-snapshots)
   - Disables automatic snapshots after interactive operations
   - browser_snapshot tool always works for explicit snapshots
   - Maintains backward compatibility (snapshots enabled by default)

3. **Differential snapshots** (--differential-snapshots)
   - Shows only changes since last snapshot instead of full page
   - Tracks URL, title, DOM structure, and console activity
   - Significantly reduces token usage for incremental operations

4. **Enhanced tool descriptions**
   - All interactive tools now document snapshot behavior
   - Clear guidance on when snapshots are included/excluded
   - Helpful suggestions for users experiencing token limits

Configuration options:
- CLI: --no-snapshots, --max-snapshot-tokens N, --differential-snapshots
- ENV: PLAYWRIGHT_MCP_INCLUDE_SNAPSHOTS, PLAYWRIGHT_MCP_MAX_SNAPSHOT_TOKENS, etc.
- Config file: includeSnapshots, maxSnapshotTokens, differentialSnapshots

Fixes token overflow errors while providing users full control over
snapshot behavior and response sizes.

Co-Authored-By: Claude <noreply@anthropic.com>

config.d.ts

@@ -122,4 +122,25 @@ export type Config = {
    * Whether to send image responses to the client. Can be "allow", "omit", or "auto". Defaults to "auto", which sends images if the client can display them.
    */
   imageResponses?: 'allow' | 'omit';
+
+  /**
+   * Whether to include page snapshots automatically after interactive operations like clicks.
+   * When disabled, tools will run without generating snapshots unless explicitly requested.
+   * Default is true for backward compatibility.
+   */
+  includeSnapshots?: boolean;
+
+  /**
+   * Maximum number of tokens allowed in page snapshots before truncation.
+   * When a snapshot exceeds this limit, it will be truncated with a helpful message.
+   * Use 0 to disable truncation. Default is 10000.
+   */
+  maxSnapshotTokens?: number;
+
+  /**
+   * Enable differential snapshots that only show changes since the last snapshot.
+   * When enabled, tools will show page changes instead of full snapshots.
+   * Default is false.
+   */
+  differentialSnapshots?: boolean;
 };