chore(deps)(deps): bump tiktoken-rs from 0.11.0 to 0.12.0 in /diffctx (#64)

Bumps [tiktoken-rs](https://github.com/zurawiki/tiktoken-rs) from 0.11.0 to 0.12.0.
- [Release notes](https://github.com/zurawiki/tiktoken-rs/releases)
- [Commits](zurawiki/tiktoken-rs@v0.11.0...v0.12.0)

---
updated-dependencies:
- dependency-name: tiktoken-rs
  dependency-version: 0.12.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

diffctx/Cargo.lock

@@ -104,7 +104,7 @@ tree-sitter-graphql = { version = "0.1", optional = true }
 tree-sitter-dart = { version = "0.1", optional = true }
 tree-sitter-prisma-io = { version = "1.6", optional = true }
 tree-sitter-svelte-ng = { version = "1.0", optional = true }
-tiktoken-rs = "=0.11.0"
+tiktoken-rs = "=0.12.0"
 rayon = "1.10"
 serde = { version = "1", features = ["derive", "rc"] }
 serde_json = "1"