* feat(compiler): add compile start/complete notifications
Problem: No user-facing feedback when compilation starts or finishes.
Long-running compilers like pandoc with `--embed-resources` leave the
user staring at nothing for 15+ seconds.
Solution: Notify "compiling..." at compile start and "compilation
complete" on success. The initial `toggle` call uses a combined
"compiling with <name>..." message to avoid stacking two notifications.
* refactor(presets): use `--katex` instead of `--embed-resources --mathml`
Problem: `--embed-resources` with `--mathml` caused pandoc to inline all
assets at compile time, adding ~15s per save for KaTeX-heavy documents.
Solution: Default to `--katex`, which inserts a CDN `<script>` tag and
defers rendering to the browser. Users can opt into `--embed-resources`
or `--mathml` via `extra_args`.
* docs(presets): rewrite math rendering section for `--katex` default
* refactor(compiler): simplify notification flow, add failure notify
Problem: `compile()` used an `opts.silent` escape hatch so `toggle()`
could suppress duplicate notifications. Compilation failures had no
user-facing notification.
Solution: Remove `opts.silent` — `compile()` unconditionally notifies
on start, success, and failure. `toggle()` no longer emits its own
message.
* feat(compiler): add per-recompile notifications for long-running providers
Problem: long-running providers like `typst watch` had no per-recompile
feedback — the process stays alive and individual success/failure was
never reported.
Solution: add a persistent `output_watcher` fs_event that fires
"compilation complete" on every output mtime bump, and track
`has_errors` on `BufState` so stderr diagnostics trigger a one-shot
"compilation failed" notification. `diagnostic.set()` now returns the
diagnostic count to support this flow.
* ci: format
* chore: remove testing files
Problem: all three built-in error parsers were broken against real
compiler output. Typst set source to the relative file path, overriding
the provider name. LaTeX errors go to stdout but the parser only
received stderr. Pandoc's pattern matched "Error at" but not the real
"Error parsing YAML metadata at" format, and single-line parsing missed
multiline messages.
Solution: pass combined stdout+stderr to error_parser so LaTeX stdout
errors are visible. Remove source = file from the Typst parser so
diagnostic.lua defaults it to the provider name. Rewrite the Pandoc
parser with line-based lookahead: match (line N, column N) regardless
of prefix text, skip YAML parse exception lines when looking ahead for
the human-readable message. Rename stderr param to output throughout
diagnostic.lua, presets.lua, and init.lua annotations.
