chore: claudbエイリアス整理と.serena/.gitignore追加 (#2)

* chore: claudbエイリアス整理と.serena/.gitignore追加

- containers/base/Dockerfile: claudbエイリアスからANTHROPIC_MODEL/ANTHROPIC_SMALL_FAST_MODELを削除（Bedrockプロファイル側で管理）
- .serena/.gitignore を新設し、serena_config.yml/logs/cache/language_servers をディレクトリ内で除外
- ルート.gitignore からは .serena/serena_config.yml の個別指定を削除（.serena/.gitignore に統合）

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore: claudeエイリアスからANTHROPIC_BETAを削除

context-1m-2025-08-07 ベータヘッダーの指定を削除し、デフォルト挙動に統一。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: takemi-ohama

.gitignore

@@ -8,5 +8,4 @@ plugins/*/
 !plugins/.gitkeep
 projects/*
 !projects/.gitkeep
-.serena/serena_config.yml
 .env.sources.yml

.serena/.gitignore

@@ -0,0 +1,4 @@
+serena_config.yml
+logs/
+cache/
+language_servers/

containers/base/Dockerfile

@@ -146,8 +146,8 @@ RUN set -eux; \
 RUN set -eux; \
     # AI CLI aliases
     echo 'export PATH="$HOME/.local/bin:$PATH"' >> ~/.bashrc; \
-    echo 'alias claude='\''ANTHROPIC_BETA=context-1m-2025-08-07 claude --dangerously-skip-permissions "$@"'\''' >> ~/.bashrc; \
-    echo 'alias claudb='\''CLAUDE_CODE_USE_BEDROCK=1 AWS_REGION=us-west-2 ANTHROPIC_MODEL=us.anthropic.claude-opus-4-6 ANTHROPIC_SMALL_FAST_MODEL=global.anthropic.claude-haiku-4-5-20251001-v1:0 claude --dangerously-skip-permissions "$@"'\''' >> ~/.bashrc; \
+    echo 'alias claude='\''claude --dangerously-skip-permissions "$@"'\''' >> ~/.bashrc; \
+    echo 'alias claudb='\''CLAUDE_CODE_USE_BEDROCK=1 AWS_REGION=us-west-2 claude --dangerously-skip-permissions "$@"'\''' >> ~/.bashrc; \
     echo 'alias gemini='\''GOOGLE_GENAI_USE_VERTEXAI=true gemini --yolo "$@"'\''' >> ~/.bashrc; \
     echo 'alias codex='\''codex --dangerously-bypass-approvals-and-sandbox "$@"'\''' >> ~/.bashrc; \
     echo 'alias kiro='\''kiro-cli chat --trust-all-tools "$@"'\''' >> ~/.bashrc; \