Replace deprecated Copilot Edit Mode with Agent Mode throughout workshop

[Claude]

GitHub Copilot Edit Mode has been deprecated. Workshop step 3 relied on this feature, but its results are required for subsequent steps, so removal wasn't an option.

Changes

• Step 3 (3-copilot-edits.md): Added deprecation notice at top. Replaced Edit Mode instructions with Agent Mode equivalents:

  • Updated theory section and workflow diagram to reflect Agent Mode's autonomous approach
  • Changed activity to use #codebase tool instead of manual file selection
  • Simplified prompt to leverage Agent Mode's file discovery capabilities

• Step 1 (1-preparing.md): Removed Edit Mode from interaction modes comparison table

• Step 4 (4-copilot-agent-mode.md): Replaced "Edit vs Agent Mode" comparison table with bullet list of Agent Mode capabilities

• Review (x-review.md): Consolidated Edit and Agent Mode mentions in recap

The workshop flow and expected outcomes (modifications to src/static/) remain unchanged. Participants now use Agent Mode exclusively for multi-file edits.

Original prompt

Copilot edit mode is being deprecated. This means that the workshop related to copilot edit (step 3) will not work as explained.
We cannot remove the result of that step because it is required for future steps, so we need to adjust and replace all Edit indications to use the Agent mode instead.
Its okay to start the exercise with the same title, but we should add a notice mentioning the deprecation of the feature, and that as a workaround we'll use the Agent mode instead.