* fix(buffer): keep conceal active in all modes and add `%l` EOL forge labels
Problem: `concealcursor` was missing `i` and `v`, so concealed text
(task IDs, forge tokens) leaked in insert and visual modes. Forge
labels only rendered for the first span when multiple refs existed.
Solution: set `concealcursor = 'nicv'` to keep conceal in all modes.
Add `%l` EOL format specifier that renders all forge spans with
independent highlights. Update default `eol_format` to include `%l`.
* refactor: remove `- ` prefix from task line rendering
Problem: task lines rendered as `- [ ] description` with a redundant
markdown list marker prefix that added visual noise.
Solution: render task lines as `[ ] description` instead. Update all
line generation in `views.lua`, parsing patterns in `buffer.lua`,
`diff.lua`, `textobj.lua`, syntax rules, and corresponding specs.
98e4abffc7