fix(bots): use thin LTO and Cargo.lock in rusher build

- Switch from full LTO (lto=true) to thin LTO to avoid memory/ICE issues
- Include Cargo.lock in Dockerfile for reproducible dependency resolution
- Use opt-level='s' (balanced size/speed) instead of 'z' (max size opt)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

bots/rusher/Cargo.toml

@@ -16,5 +16,5 @@ tracing-subscriber = "0.3"
 
 [profile.release]
 strip = true
-opt-level = "z"
-lto = true
+opt-level = "s"
+lto = "thin"

bots/rusher/Dockerfile

@@ -2,7 +2,7 @@
 FROM rust:1.85-alpine AS builder
 
 WORKDIR /app
-COPY Cargo.toml ./
+COPY Cargo.toml Cargo.lock ./
 COPY src ./src
 
 RUN cargo build --release