feat(core): Implement JIT context manager and setting

[SandyTao520]

TLDR

Introduces the ContextManager service and experimental.jitContext setting to enable Just-In-Time context loading, leveraging the granular memory loaders.

Dive Deeper

• Adds experimental.jitContext boolean setting (default: false).
• Updates Config to initialize ContextManager only when the flag is enabled.
• ContextManager uses loadJitSubdirectoryMemory to discover and load GEMINI.md files from the accessed path upwards to the trusted root.
• Tracks loaded paths to prevent duplicates.
• Moves globalMemory and environmentMemory state to ContextManager and exposes getters in Config for the new tiered architecture.
• Wires up the setting in CLI config.

Reviewer Test Plan

1. Enable experimental.jitContext in settings (e.g. settings.json).
2. Verify config.experimentalJitContext is true.
3. Verify config.contextManager is initialized.
4. Verify contextManager.discoverContext loads expected files when provided with a path.

Testing Matrix

	🍏	🪟	🐧
npm run	✅	❓	❓
npx	✅	❓	❓
Docker	❓	❓	❓
Podman	❓	-	-
Seatbelt	❓	-	-

Linked issues / bugs

Resolves #11978

[gemini-code-assist[bot]]

Summary of Changes

Hello @SandyTao520, I'm Gemini Code Assist[^1]! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a new Just-In-Time (JIT) context loading mechanism, controlled by an experimental setting. It centralizes context management through a dedicated ContextManager service, which dynamically loads GEMINI.md files based on accessed paths, aiming to optimize memory usage and context relevance.

Highlights

• New Experimental Setting: Introduces an experimental.jitContext boolean setting, defaulting to false, to control Just-In-Time context loading.
• ContextManager Service: A new ContextManager service is added, initialized by the Config class only when the experimental.jitContext flag is enabled.
• JIT Context Loading Logic: The ContextManager utilizes loadJitSubdirectoryMemory to dynamically discover and load GEMINI.md files, traversing upwards from the accessed path to the trusted root.
• Path Tracking: The ContextManager tracks already loaded paths to prevent redundant loading of context files.
• Tiered Memory Architecture: The state for globalMemory and environmentMemory is moved into the ContextManager, and the Config class now exposes getters for this new tiered memory architecture.
• CLI Integration: The new experimental.jitContext setting is wired up and configurable within the CLI.

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[github-actions[bot]]

Size Change: +3.91 kB (+0.02%)

Total Size: 21.5 MB

Filename	Size	Change
./bundle/gemini.js	21.4 MB	+3.91 kB (+0.02%)

ℹ️ View Unchanged

Filename	Size
./bundle/sandbox-macos-permissive-closed.sb	1.03 kB
./bundle/sandbox-macos-permissive-open.sb	890 B
./bundle/sandbox-macos-permissive-proxied.sb	1.31 kB
./bundle/sandbox-macos-restrictive-closed.sb	3.29 kB
./bundle/sandbox-macos-restrictive-open.sb	3.36 kB
./bundle/sandbox-macos-restrictive-proxied.sb	3.56 kB

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