feat(markdown): inline [label](url) link parsing in MarkdownInline (M1, @since 1.6.8)

[DemchaAV]

Summary

Headline feature for the v1.6.8 cycle — closes the CV v2
migration gap where project / education / experience entry titles
could not be rendered as hyperlinks.

The renderer pipeline already had the output primitive
(RichText.link(text, uri) — used by the CV header's contact
links since v1.6.0). What was missing was the inline-markdown
adapter that every body / row / entry renderer routes through
recognising the [label](url) syntax. After this PR it does.

Implementation

MarkdownInline.append(rich, text, baseStyle) gets a pre-pass
that scans for [text](url) matches:

• Each match emits exactly one rich.link(text, url) run.
• Plain segments between (or surrounding) link matches flow
  through the existing MarkdownText emphasis pipeline unchanged
  — **bold** / *italic* / _italic_ still work as before.
• MarkdownInline.plainText(value) is updated in lockstep:
  [label](url) collapses to just label. Callers that need
  the visible-text projection (ProjectLabel.parse uses this
  for the project title) keep getting clean output.
• One shared LINK_PATTERN regex constant for both paths so the
  two views agree on what counts as a link.

What this PR does NOT touch

• ProjectRenderer / EntryRenderer — they currently call
  rich.style(...) directly on the title segment instead of
  routing through MarkdownInline.append, so a [text](url) in
  a CvRow.label still won't render as a link in the existing
  layered presets. That's deliberately scoped to Track M3 (a
  separate focused PR) so this PR stays a pure parser change with
  japicmp-clean public-API extension.
• CvRow record shape — no new field, no breaking change.
  The link information rides inside the existing label string.

Design tradeoffs

• v1 does not honour emphasis inside the link label
  ([**bold**](url) renders as a single link run with literal
  asterisks; outside emphasis works fine). Recursive parsing
  inside the label is a v2 candidate.
• v1 does not support nested brackets [a [b] c](url) —
  the regex requires no inner brackets. Document authors hit
  by this can restructure the label.
• Empty link text [](url) is matched and emits an empty-text
  link run. Unusual but legal.

Test plan

• New MarkdownInlineTest (12 tests):
  • plainText strips link syntax, combines with emphasis strip,
    leaves bare brackets intact, handles multiple links, handles
    null safely (5 tests).
  • append emits exactly one hyperlink run with the correct
    text + uri for [text](url), mixes plain + emphasis + link,
    preserves ordering of multiple links, leaves bare brackets
    as literal, keeps ** / * / _ emphasis working without
    links, null/empty no-op, appendTrimmed strips whitespace
    then parses (7 tests).
• ./mvnw verify -pl . -P japicmp — 1049 tests, 0
  failures; japicmp vs v1.6.7 baseline: semver PATCH
  (compatible behaviour extension on existing public
  methods, no signature change).