Patch/inject: plain-code inline, inject() API, range capture, logger

- Inline prompts: use plain 'replace selection' prompt instead of SEARCH/REPLACE
- Add codetyper.inject.inject(bufnr, code, opts) for patch apply (replace/insert/append)
- Patch: on SEARCH/REPLACE failure use REPLACE parts only; inline always replace range
- Fix 0-0 range: clamp in create_from_event, prefer scope_range when invalid
- Commands: capture injection range from selection (derive end from line count); no selection = whole file
- Commands: log injection range; pass injection_range in prompt; autocmds prefer it
- Replace diagnostic logs with codetyper.support.logger in patch and scheduler
- Fix patch apply syntax (code_to_inject variable for multi-line logger call)

Co-authored-by: Cursor <cursoragent@cursor.com>

doc/codetyper.txt

@@ -263,11 +263,6 @@ The plugin detects the type of request from your prompt:
 :CoderTransformVisual
     Transform selected /@ @/ tags (visual mode).
 
-                                                         *:CoderIndex*
-:CoderIndex
-    Open coder companion file for current source file.
-
-                                                          *:CoderLogs*
 :CoderLogs
     Toggle the logs panel showing LLM request details.