filter(webpack): add webpack build filter

[mpecan]

Goal

Add a filter for webpack and webpack-cli builds — a widely used JavaScript bundler that produces verbose asset and chunk tables even on successful builds.

Background

Default webpack output includes:

• Full chunk dependency graphs listing every module in each chunk
• Entrypoint tables showing all included assets
• Per-asset size tables (useful once, noisy in CI on every build)
• Plugin log messages (some plugins like mini-css-extract-plugin are notoriously verbose — community issue #496 titled "Output logging is too verbose")

Actual errors and warnings are interspersed with this structural output, making failures hard to spot.

Filters to Add

webpack/build.toml — webpack / webpack-cli / webpack --mode production

• Skip:
  • Module count lines (X modules)
  • Chunk entrypoint tables (lines under Entrypoint <name> =)
  • Asset size table lines when build succeeds (lines matching <asset> <size> <chunks>)
  • [webpack-dev-middleware] informational lines
• Keep:
  • ERROR in lines with file reference
  • WARNING in lines (these are usually actionable)
  • webpack compiled with X errors or webpack compiled successfully summary
  • Lines referencing bundle size limit exceeded warnings

webpack/watch.toml — webpack --watch / webpack serve

• Skip: routine recompile start/end messages when no errors (webpack compiled successfully in Xms)
• Keep: recompile messages that include errors or warnings, [HMR] disconnect/reconnect messages

Fixture Files Needed

• tests/fixtures/webpack/build-success.txt — successful production build with full stats output
• tests/fixtures/webpack/build-errors.txt — build with module errors
• tests/fixtures/webpack/build-warnings.txt — build with size limit warnings

Acceptance Criteria

• Asset/chunk tables removed from successful build output
• ERROR in and WARNING in lines always preserved
• Build outcome summary line always preserved
• Integration tests pass for all fixture files