chore(server): improve transcript stability (#13821)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Enhanced audio/video detection for MP4 files to better distinguish
audio-only vs. video.

* **Dependencies**
* Added MP4 parsing dependency and updated AI provider libraries
(Anthropic, Google, OpenAI, etc.).

* **Bug Fixes**
  * Tightened authentication state validation for magic-link/OTP flows.
* Stricter space-join validation to reject invalid client
types/versions.
  * Improved transcript entry deduplication and data handling.

* **API**
* Transcript submit payload now requires infos and removes deprecated
url/mimeType fields.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Cargo.lock

@@ -163,6 +163,7 @@ dependencies = [
  "file-format",
  "infer",
  "mimalloc",
+ "mp4parse",
  "napi",
  "napi-build",
  "napi-derive",
@@ -574,6 +575,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "bitreader"
+version = "0.3.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "886559b1e163d56c765bc3a985febb4eee8009f625244511d8ee3c432e08c066"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "bitvec"
 version = "1.0.1"
@@ -1483,6 +1493,15 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af9673d8203fcb076b19dfd17e38b3d4ae9f44959416ea532ce72415a6020365"
 
+[[package]]
+name = "fallible_collections"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a88c69768c0a15262df21899142bc6df9b9b823546d4b4b9a7bc2d6c448ec6fd"
+dependencies = [
+ "hashbrown 0.13.2",
+]
+
 [[package]]
 name = "fancy-regex"
 version = "0.13.0"
@@ -1801,6 +1820,15 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.13.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43a3c133739dddd0d2990f9a4bdf8eb4b21ef50e4851ca85ab661199821d510e"
+dependencies = [
+ "ahash",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.14.5"
@@ -2494,6 +2522,20 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "mp4parse"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63a35203d3c6ce92d5251c77520acb2e57108c88728695aa883f70023624c570"
+dependencies = [
+ "bitreader",
+ "byteorder",
+ "fallible_collections",
+ "log",
+ "num-traits",
+ "static_assertions",
+]
+
 [[package]]
 name = "nanoid"
 version = "0.4.0"