Extend the plugins' isolation surface area

[lyssieth]

Expands the surface area of what we (currently pretend to) isolate (so in the future we can actually do it) to a few new fields.

Filesystem, and critically due to the GitHub plugin, cryptography.
SDK + Plugins require a version bump due to this too. Publishing once PR is merged.

[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between 0de9afd and 3fcd39e.

📒 Files selected for processing (13)

• docs/plugins/developers.md
• packages/brave-search/package.json
• packages/openweather/package.json
• packages/plugin-github/package.json
• packages/plugin-github/src/auth.ts
• packages/runtime/src/engine/index.ts
• packages/runtime/src/plugin/loader.ts
• packages/runtime/src/plugin/worker-main.ts
• packages/sdk/package.json
• packages/sdk/src/encoding.ts
• packages/sdk/src/index.ts
• packages/sdk/src/tool.ts
• packages/template/package.json

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📝 Walkthrough

Walkthrough

This PR extends the plugin runtime with WebCrypto-based key normalization and sandboxed filesystem operations. The SDK defines types and encoding utilities; the runtime implements RPC handlers for crypto and filesystem access with access control; workers expose these as plugin APIs; the GitHub plugin refactors JWT signing to use the new async crypto; and all dependencies are updated.

Changes

Plugin crypto and filesystem capabilities

Layer / File(s)	Summary
SDK type contracts and encoding utilities packages/sdk/src/tool.ts, packages/sdk/src/encoding.ts, packages/sdk/src/index.ts, packages/sdk/package.json	WebCryptoFormat, FsApi, FsDirent, FsStat types define the plugin tool context contract; pemToDer and base64url encode/decode utilities enable key format conversion; version bumped to 0.5.0.
Runtime RPC handlers for crypto and filesystem packages/runtime/src/plugin/loader.ts, packages/runtime/src/engine/index.ts	Engine and loader register RPC handlers for key normalization (crypto.loadNormalizedKey) and sandboxed filesystem ops (readTextFile, writeTextFile, stat, listDir), enforcing path resolution and access control.
Worker context building for plugin access packages/runtime/src/plugin/worker-main.ts	buildCtx exposes RPC-backed crypto and fs APIs to plugin code, forwarding method calls to corresponding RPC handlers.
GitHub plugin JWT signing refactor packages/plugin-github/src/auth.ts, packages/plugin-github/package.json	JWT generation switches from synchronous Node crypto to async WebCrypto flow using ctx.crypto.loadNormalizedKey and SDK utilities; generateJWT becomes async and uses crypto.subtle.sign for RS256 signing.
Package version and dependency updates packages/brave-search/package.json, packages/openweather/package.json, packages/template/package.json	Peer and dev dependencies on @cireilclaw/sdk updated to ^0.5.0 across plugin packages.
Developer guide documentation docs/plugins/developers.md	Documentation extended to include crypto.loadNormalizedKey, filesystem methods (readTextFile, writeTextFile, stat, listDir), and SDK exports (pemToDer, base64urlEncode, base64urlDecode).

Possibly related PRs

• CutieZone/CireilClaw#19: Refactors the GitHub plugin auth to use WebCrypto-based JWT signing with the new ctx.crypto.loadNormalizedKey and SDK encoding utilities.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately reflects the primary objective of the PR: extending the plugins' isolation surface area with new crypto and filesystem capabilities.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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