feat(context): improve inline selection formatting

Update the inline visual selection text to use bolded file path formatting
(**`path/to/file`**) instead of the previous "Here is some code from"
prefix. Adjust unit tests to match the new output format. This change
makes the inserted context more visually distinct and concise.

Author: jugarpeupv

lua/opencode/context.lua

@@ -168,7 +168,7 @@ end
 --- Captures the current visual selection and returns the text to be inserted inline
 --- into the opencode input buffer, in the form:
 ---
----   Here is some code from <file-path>:
+---   **`path/to/file`**
 ---
 ---   ```<filetype>
 ---   <selected text>
@@ -198,7 +198,7 @@ function M.build_inline_selection_text(range)
 
   local filetype = vim.bo[buf].filetype or ''
   local text = string.format(
-    'Here is some code from %s:\n\n```%s\n%s\n```',
+    '**`%s`**\n\n```%s\n%s\n```',
     file.path,
     filetype,
     current_selection.text

tests/unit/context_spec.lua

@@ -1182,7 +1182,7 @@ describe('build_inline_selection_text', function()
     local text = context.build_inline_selection_text()
 
     assert.is_not_nil(text)
-    assert.is_not_nil(text:match('Here is some code from /tmp/test%.lua:'))
+    assert.is_not_nil(text:match('%*%*`/tmp/test%.lua`%*%*'))
     assert.is_not_nil(text:match('```lua'))
     assert.is_not_nil(text:match('function foo%(%)'))
     assert.is_not_nil(text:match('```$'))