fix: keep rune and repeat bundles conductor-safe

[martin-henz]

Re-opens #837, which was automatically closed (not merged) when its base branch conductor-migration was deleted after being merged into master via #680. This branch cherry-picks the original commits from @11suixing11 unchanged, onto current master.

Summary

• replace rune/repeat Conductor bundle imports from modules-lib errors/utilities with Conductor errors/assertions or local pure helpers
• keep repeat_internal synchronous without callWithoutMetadata so rune can import repeat without pulling js-slang externals
• add local hexToColor/hueToRgb helpers used by rune color functions

Fixes #825

Testing (from original PR, re-verify on CI)

• yarn workspace @sourceacademy/bundle-rune test
• yarn workspace @sourceacademy/bundle-repeat test
• yarn workspace @sourceacademy/bundle-rune tsc
• yarn workspace @sourceacademy/bundle-repeat tsc
• yarn workspace @sourceacademy/bundle-rune lint
• yarn workspace @sourceacademy/bundle-repeat lint (passes with existing IModuleExport warning)
• rg "js-slang|@sourceacademy/modules-lib/(errors|utilities)|assertNumberWithinRange|callWithoutMetadata|InvalidParameterTypeError|GeneralRuntimeError" build/bundles/rune.js build/bundles/repeat.js -n (no matches)

Original author: @11suixing11

[gemini-code-assist]

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