[falbany]

Two independent editor fixes found while using the config editor on main.

1. Dark-theme syntax palette (f7c97d3, follows up #98)

Root cause of the bad dark-theme colors: the editor inherited CodeMirror's defaultHighlightStyle through basicSetup (fallback: true) — a light-background palette (#940 browns, #164 teals, #00c navy, #708 purple) that is nearly unreadable on the dark #1e1e1e canvas. Every YAML key, string and comment on the dark canvas was drawn with washed-out dark-on-dark colors.

Fix: a NON-fallback HighlightStyle mapping the tags the YAML parser actually emits (@lezer/yaml styleTags) onto new --app-editor-syntax-* tokens, defined in both theme blocks like every --app-editor-* token (issue #98 pattern):

Token	Dark+	Light+	Applies to
--app-editor-syntax-key	#9cdcfe	#0451a5	keys (propertyName + definition)
--app-editor-syntax-string	#ce9178	#a31515	quoted strings and plain/block scalars (tags.content)
--app-editor-syntax-comment	#6a9955	#008000	comments
--app-editor-syntax-keyword	#569cd6	#0000ff	directives, YAML tags
--app-editor-syntax-label	#4ec9b0	#267f99	anchors & aliases

var() references make the palette follow the light/dark switch automatically. @codemirror/language and @lezer/highlight are now declared direct dependencies. dist rebuilt.

2. Multi-issue validation report (01ce306)

Investigation result: the editor showed only the first error because everything was exception-based and fail-fast — validate_issues() caught a single ValueError from ConfigReader.from_content, whose pipeline (strict parse → semantic validate → Pydantic schema) raises at the first violation. Fix one error, and the next one appeared on the next Test.

Fix: new core module profiles.core.config.diagnostics — collect_config_issues(text) reports every problem without raising:

• YAML syntax error → single issue (the ruamel parser stops there — no tree exists to validate until it's fixed; documented limitation)
• semantic issues collected exhaustively — every unknown top-level key, every unknown extends, every cycle (validator.collect_issues; validate() keeps its fail-fast contract, implemented on top of it — DRY)
• every Pydantic schema error with its dotted path

/api/config/validate, /save and /save-as gates now receive the full issue list; the drop-overlay path keeps from_content unchanged.

Before → after for one draft (relese: typo, bad extends, an a↔b cycle, wrong theme, search_dir: 42, negative depth):

error | relese: unknown top-level key 'relese'
error | configs.prod.extends: unknown config 'ghost'
error | configs.b.extends: inheritance cycle: a -> a -> b -> a
error | defaults.theme: Input should be 'light', 'dark' or 'auto'
error | defaults.search_dir: Input should be a valid string
error | defaults.max_search_depth: Input should be greater than or equal to 0

— previously only the first of these was displayed.

Verification

• Web: 242 tests passed (14 files) — new syntax-palette test; tsc -b clean; dist rebuilt.
• Python: 40 passed in the touched areas (new collect_issues + collect_config_issues suites + /validate multi-issue test). Full suite: failures unchanged in touched areas; the delta vs the Windows baseline (test_save_image_delegates_to_core_and_reports_path path separators, test_build_env_falls_back_to_node_dirs node PATH) is environmental and unrelated.
• ruff check + ruff format clean; AGENTS.md and tests/AGENTS.md trees updated for the new module.