perf: remove unused tiktoken-rs and chromiumoxide dependencies

Remove heavy dependencies that were declared but never used in code:
- tiktoken-rs: not imported or used anywhere (tokenizer.rs uses simple estimation)
- chromiumoxide: not imported or used anywhere

These dependencies were adding significant startup time overhead
(~1-3 seconds combined) without providing any functionality.

Fixes CLI startup performance issues documented in CLI_PERFORMANCE_ANALYSIS.md

Author: factorydroid

Cargo.lock

@@ -359,7 +359,6 @@ bitflags = "2.6"
 slotmap = "1.0"
 parking_lot = "0.12"
 flume = "0.11"
-tiktoken-rs = "0.6"
 secrecy = { version = "0.10", features = ["serde"] }
 zeroize = { version = "1.8", features = ["derive"] }
 glob = "0.3"

Cargo.toml

@@ -103,17 +103,11 @@ aes-gcm = "0.10"
 argon2 = "0.5"
 zeroize = { version = "1.8", features = ["derive"] }
 
-# Tiktoken for token counting
-tiktoken-rs = "0.6"
-
 # mDNS / Service Discovery
 mdns-sd = { workspace = true }
 hostname = { workspace = true }
 flume = "0.11"
 
-# Headless Browser
-chromiumoxide = { version = "0.7", default-features = false, features = ["tokio-runtime"] }
-
 # Platform specific
 [target.'cfg(target_os = "linux")'.dependencies]
 landlock = { workspace = true }