feat(claude/commands): support staged-only commits and add git diff permission

Allow commit commands to operate on only staged changes when requested,
rather than always staging everything. This enables more granular control
over what gets committed.

- Add `Bash(git diff:*)` to allowed-tools in both commit and
  commit-push-pr commands
- Add instructions to check staged changes with `git diff --staged`
  and skip staging additional files when asked for staged-only commits
- Restructure commit.md flow to clarify staged-only vs full commit

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

claude/commands/commit.md

@@ -1,5 +1,5 @@
 ---
-allowed-tools: Bash(git add:*), Bash(git status:*), Bash(git commit:*)
+allowed-tools: Bash(git add:*), Bash(git diff:*), Bash(git status:*), Bash(git commit:*)
 description: Create a git commit
 source: https://github.com/anthropics/claude-plugins-official/blob/main/plugins/commit-commands/commands/commit.md
 ---
@@ -15,6 +15,12 @@ source: https://github.com/anthropics/claude-plugins-official/blob/main/plugins/
 
 Based on the above changes, create a single git commit.
 
-You have the capability to call multiple tools in a single response. Stage and
-create the commit using a single message. Do not use any other tools or do
-anything else. Do not send any other text or messages besides these tool calls.
+If asked to commit only staged changes, run `git diff --staged` to see exactly
+what is staged, and base the commit message solely on those changes. Do NOT
+stage additional files.
+
+Otherwise, stage all relevant changes and create the commit.
+
+You have the capability to call multiple tools in a single response. Do not use
+any other tools or do anything else. Do not send any other text or messages
+besides these tool calls.