MonacoEditor: schema store, YAML and Turtle languages, shadow-root fixes, shared bundle

[simontaurus]

Extends the MonacoEditor panel with what the OO-LD schema-playground (https://github.com/OO-LD/oold-playgrounds/tree/master/schema-playground) needed in practice.

• schema_store (new param): schemas keyed by the URI a buffer's own $schema names. Monaco's JSON service gives an in-document $schema pointer precedence over any fileMatch association, and nothing is ever fetched, so a document that declares $schema - every OO-LD document does - got no validation and no completion from json_schema at all. Registering a local copy under that URI resolves the pointer offline. Relative keys resolve against the in-memory folder the editor models live in, mirroring how the JSON service resolves a relative $schema. Verified with Playwright: with the store, an invalid document shows markers and property completion works; without it, neither.
• YAML: Monarch highlighting plus the monaco-yaml language service (validation, completion, hover against the same schemas; YAML has no in-document $schema, so fileMatch is its only association).
• Turtle tokenizer: a Monarch grammar (IRIs, prefixed names, literals with datatype or language tag, @prefix/@base, comments), since monaco ships no Turtle language.
• schema_request severity and enable_schema_request: how loudly an unresolvable $schema pointer is reported (error/warning/ignore), and an opt-in that lets the pointer and remote $refs fetch live (CORS permitting). Both page-wide, as monaco exposes them.
• ready flag: set from the browser once the editor exists. Monaco boots long after the page, so a host that wants a boot signal needs this, not the page load event.
• Bundle via import map: _esm is a per-instance model property, so a page with 24 editors shipped the 6.6 MB bundle 24 times (a 168 MB document). A two-line shim re-exports the module from a pinned CDN URL, fetched and cached once; PANELINI_MONACO_BUNDLE overrides the URL or inlines it for offline use. The pin names the commit that carries the committed js/dist.
• One JSON-service update per schema batch instead of a reconfiguration per editor.
• Shadow-root fixes: suggest rows stay readable (shadow retargeting breaks monaco's focus tracking, painting focused-row white on the widget's near-white ground) and are shielded from host layout CSS that Panel distributes into shadow roots (a host .main { padding-top } pushed every label out of its 16px row); hover tooltips and the codicon font render inside the shadow root.
• Clean console: monaco's speculative fetch of a relative $schema against the models' inmemory:// base is rejected before the native call instead of surfacing as a browser error.
• self.monaco: the ESM build never assigns the global the AMD loader would, so the API is exposed for outside automation and debugging.

js/dist is rebuilt and committed, matching how this branch ships its bundle.

[github-actions]

Release preview

Merging this PR would release 0.12.0 (current: 0.11.0).

Changelog preview (truncated)

## v0.12.0 (2026-09-17)

### Bug Fixes

- **monacoeditor**: Guard optional viewport_size in the OO-LD example test
  ([`1f341c7`](https://github.com/opensemanticworld/panelini/commit/1f341c72861f43844537bbd27e5b7606a7d1e6d8))

- **monacoeditor**: No console error for inmemory:// schema requests
  ([`5a4bccf`](https://github.com/opensemanticworld/panelini/commit/5a4bccf85a052b477879e23e31fc2f4a6300297b))

- **monacoeditor**: Readable suggest rows inside a shadow root
  ([`23a0ee2`](https://github.com/opensemanticworld/panelini/commit/23a0ee2ca842766b28c2392c37d24272ceecf76d))

- **monacoeditor**: Repoint the CDN bundle pin at the current dist
  ([`787ee9b`](https://github.com/opensemanticworld/panelini/commit/787ee9b1d392e8cdbca1f0c16f3824694193c0f1))

- **monacoeditor**: Shield suggest rows from host layout CSS
  ([`6509388`](https://github.com/opensemanticworld/panelini/commit/6509388cda31837f54ecc20371e0a8a18dfc7422))

- **monacoeditor**: Show hover tooltips and icons in the shadow root
  ([`5c407ec`](https://github.com/opensemanticworld/panelini/commit/5c407ecb4869073acdbb1055cae83c25766ca07f))

- **monacoeditor**: Stretch editor width so it is usable
  ([`20eec19`](https://github.com/opensemanticworld/panelini/commit/20eec19da23cef0479792f83e8338abc30f0fbff))

### Build System

- **monacoeditor**: Bundle monaco-editor for the panel
  ([`41e818d`](https://github.com/opensemanticworld/panelini/commit/41e818d1f23a22d9f76ba96d6dc8ac503955770a))

### Chores

- **monacoeditor**: Repoint the CDN bundle pin at the rebuilt dist
  ([`38123ad`](https://github.com/opensemanticworld/panelini/commit/38123add1831d68b935dcb12df7ae408f08262ee))

### Continuous Integration

- Monacoeditor render selector; keep fixers out of generated bundles
  ([`b299390`](https://github.com/opensemanticworld/panelini/commit/b2993906808ab4195c1563618a7755a00abebb8e))

### Documentation

- **examples**: Add minimal monacoeditor schema and data editor example
  ([`45a44de`](https://github.com/opensemanticworld/panelini/commit/45a44de4beb430aa88dd5434b08e573cd3162435))

### Features

- **monacoeditor**: Add MonacoEditor panel
  ([`7273b48`](https://github.com/opensemanticworld/panelini/commit/7273b48da6f98346b24854107f0bcb4d22737c16))

- **monacoeditor**: Add schema_request severity and an OO-LD example
  ([`d09b4d7`](https://github.com/opensemanticworld/panelini/commit/d09b4d720064582a7f66edb02fb83ccf5721dce7))

- **monacoeditor**: Expose the monaco API as self.monaco
  ([`a748bb7`](https://github.com/opensemanticworld/panelini/commit/a748bb7cbbab8798b6abe8e858e013968dbc35d6))

- **monacoeditor**: Ready flag, set once the editor exists in the browser
  ([`4e2f65c`](https://github.com/opensemanticworld/panelini/commit/4e2f65c62ee3d2bed75921346c7c6a52e0212f75))

- **monacoeditor**: Schema_store, yaml highlighting, turtle tokenizer
  ([`98612af`](https://github.com/opensemanticworld/panelini/commit/98612af88d38a62c526c88f3a47856d608cc2dff))

- **monacoeditor**: Yaml language service, schema fetch opt-in
  ([`3c09b37`](https://github.com/opensemanticworld/panelini/commit/3c09b3744758fd29b989b3acea2d1603e111f801))

### Performance Improvements

- **monacoeditor**: Coalesce schema registrations into one service update
  ([`4ba35bb`](https://github.com/opensemanticworld/panelini/commit/4ba35bbb050cae5aa7f3f0a29a17f85417a772fe))

- **monacoeditor**: Load the bundle once via import map, not per instance
  ([`2b763e2`](https://github.com/opensemanticworld/panelini/commit/2b763e2f645f640228434e263759aae4301d7082))

### Testing

- **monacoeditor**: Cover inline bundle branch for full coverage
  ([`19f6dbf`](https://github.com/opensemanticworld/panelini/commit/19f6dbfbb6b8d34dd2b980ea61fe10c11596bdf7))

- **monacoeditor**: Cover MonacoEditor JSON round-trip
  ([`c6f89ec`](https://github.com/opensemanticworld/panelini/commit/c6f89ecf3731ec26589f07bd39d479a92cb2b434))

_{Preview via python-semantic-release and conventional commits.}

[codecov]

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