fix: harden editor and tree-sitter parser for iOS Cordova (WKWebView/JSC)

[rajkumargaramie]

Closes #101

Summary

Fixes three iOS-only failures that prevented the Kerebron editor from loading in an iOS Cordova / WKWebView (JavaScriptCore) environment. All three reproduce deterministically on iOS while desktop V8/Chromium happens to avoid them, so they were only surfaced by on-device testing.

Changes

1. ExtensionManager — non-iterable extensions ({} is not iterable)

iOS JSC threw TypeError: {} is not iterable from setupExtensions/ExtensionManager. Added a toArraySafe() helper (prefers .forEach for Set/Map, falls back to Array.from, otherwise warns and returns []) and applied it at every iteration site, and replaced Map/Set for...of loops with .forEach.

2. createParser — cannot construct a Parser before calling init()

A boolean hasBeenLoaded flag was flipped to true before Parser.init() resolved, so a concurrent createParser call skipped initialization and reached new Parser() before the runtime was ready. Replaced the flag with a shared initPromise that every caller awaits (reset on failure to allow retry).

3. createParser — Invalid scheme

web-tree-sitter's findWasmBinary() still runs even when wasmBinary is supplied; without a locateFile it falls back to new URL('web-tree-sitter.wasm', import.meta.url), which throws Invalid scheme inside an iOS Cordova WKWebView. We now pass a locateFile that returns the asset name. Because wasmBinary is already provided, the returned path is never fetched.

CI

The pull_request commit-message lint and the pre-push hook iterated $(git log ...) unquoted, so each word of a subject was validated separately and no conventional-commit subject with spaces could pass; the pre-push hook additionally used origin/$BRANCH, which resolves to the ambiguous origin/HEAD under a detached-HEAD CI checkout. Both now iterate messages line by line, and the hook skips the range check when the upstream branch is unavailable.

Testing

• Verified on an iOS simulator build: the editor now opens, typing/saving work, and existing markdown content loads into the rich editor (previously it silently fell back to plain text).
• No behavior change on desktop.

[rajkumargaramie]