v15.25.0

• Update Firestore emulator to v1.22.0, adding support for DML
• Add appcheck:debugtokens:create, appcheck:debugtokens:list, and appcheck:debugtokens:delete CLI commands for managing App Check debug tokens (#10801).
• Add MCP-Protocol-Version, Mcp-Method, and Mcp-Name HTTP headers to OneMcpServer requests per the MCP 0728 standard release candidate (https://blog.modelcontextprotocol.io/posts/2026-07-28-release-candidate/ and https://modelcontextprotocol.io/seps/2243-http-standardization).
• Fixes Storage Emulator to support JSON uploads larger than 100KB without hanging or throwing 413 error (#8355)
• Add extdeprecationwarnings experiment to display phased deprecation notices and guidance across ext:* CLI commands.
• Fixes Data Connect emulator crash when in-flight GraphQL requests are cancelled (#10821)
• Fixed a Cloud Storage emulator hang under concurrent requests, caused by the rules runtime's stdout being parsed per-chunk instead of per-line so batched responses were dropped (#6194, #6865).
• Support for specifying that the input for a string or string[] param in Functions must be non-empty (#10678)
• Removed the warning that Dart functions may not yet be visible in the Firebase Console, since they are now shown.
• Add the V1 environment variable FUNCTION_REGION to v2 functions (#10862)