fix: update apply_patch format instructions to be consistent and include required space

[agreaves-ms]

ApplyPatchFormatInstructions

• Made sure the model knows to always have a space before [context_before] and [context_after]
• Made sure the model knows to always have a - before original old code lines
• Made sure the model knows to always have a + after new code lines

ApplyPatchInstructions

• Explicitly tell GPT-5 to not use ApplyPatch for create file (GPT-5 would try and create a file with apply_patch then fail over and over until eventually using the create_file tool)

Details

The apply_patch instructions and description would sometimes confuse the models and produce patches that where either missing an additional space infront of unchanging context lines, or it would consider - characters from the original text as old code lines.

[agreaves-ms]

Also, do we need these instructions? Would they limit GPT-5 at all and have GPT-5 focus on only making small simple changes?

Prefer the smallest set of changes needed to satisfy the task. Avoid reformatting unrelated code; preserve existing style and public APIs unless the task requires changes. When practical, complete all edits for a file within a single message.<br />