fix(editor): match real F∆I YAML type shape + warn on bad types

The 0.15.0 type-token coloring regex hunted for `type: <name>`,
but the F∆I YAML actually shapes types as `<fieldname>: <name>`
under `inputs:` / `outputs:` blocks. Real-world flows
(`hello.yaml`, `extract.yaml`) and module manifests (echo,
text-summarize, …) never produce the `type:` keyword unless
the operator hand-authors the long form.

Fix the regex to match an indented `KEY: VALUE` line where the
value is one of `text|json|bytes|file|number|integer`. Leading
whitespace is required so top-level keys (`name: foo`,
`version: 0.1.0`) can't false-match. This handles both
shapes — the implicit `pdf: bytes` and the explicit
`type: bytes` (used by module schema v2 inputs lists) —
because either way the pattern boils down to "key colon known
type token".

Analyzer also grows a type-token check: any inputs/outputs
field whose value isn't a known type lights up as a warning
("Unknown input type 'byes' …"), modulo `$ref` expressions
(flow outputs) and empty values (operator is mid-keystroke).

Adds `test/flow_analyzer_test.dart` with seven cases covering
empty, valid hello, unknown capability, unknown type, parse
error, version-bare matching, and the empty-installed-list
silence path.

Bumps the package to 0.15.1.

Signed-off-by: flemming-it <sf@flemming.it>

pubspec.yaml

@@ -1,6 +1,6 @@
 name: fai_studio_flow_editor
 description: Swappable inline YAML editor for F∆I Studio flows.
-version: 0.15.0
+version: 0.15.1
 publish_to: 'none'
 repository: https://git.flemming.ai/fai/studio-flow-editor