FE-698: Prompt registry + observer context-pack foundation

[lunelson]

Stack Context

This FE-698 stack establishes the prompt/context scenario substrate that future agent-heavy Brunch features can probe before UI work.

What?

• Moves interviewer, observer, and side-chat prompt text into packaged markdown assets loaded through a typed prompt registry.
• Copies prompt assets into the server-runtime build output.
• Adds the first typed observer-capture context pack seam while preserving the existing observer context rendering.

Why?

Prompt text and graph context need to become inspectable, reusable server subsystems. This PR makes prompt assets package-safe and gives observer capture the first typed context-pack boundary without changing production prompt behavior.

[lunelson]

• FE-705: Plan agent capability CLI frontier #127
• FE-698: On more context pack + spec for agent CLI v1 #114
• FE-698: Prompt/context scenario substrate foundation #111
• FE-698: Agent mutation audit; tool surface design #104
• FE-698: Design/spec/plan augmentation #103
• FE-698: Scenario runner + observer scenario composition #102
• FE-698: Prompt registry + observer context-pack foundation #101 👈 (View in Graphite)
• FE-698: Prompt/context substrate planning #98
• main

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[cursor]

PR Summary

Medium Risk
Medium risk because it changes how core LLM prompts are sourced (asset loading/interpolation) and adjusts the server-runtime build output to ship those assets; mistakes could subtly change prompt text or break runtime builds.

Overview
Externalizes server prompts into packaged markdown assets and introduces a typed prompt registry (prompt-loader.ts) with explicit interpolation and newline normalization, then updates interviewer (getSystemPrompt), observer system prompt construction, and side-chat role prompting to render via renderPromptAsset().

Introduces the first typed context-pack seam for observer capture (context-pack.ts) and rewires buildObserverContext() to render through this pack while preserving existing output via new snapshot-style tests.

Hardens build/package boundaries for prompt assets by copying src/server/prompts into dist/server/prompts during the server-runtime Vite build and adding a build-boundary test to assert the assets are present.

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[augmentcode]

🤖 Augment PR Summary

Summary: This PR introduces a packaged markdown prompt registry and the first typed context-pack slice for FE-698, moving server prompts and observer context rendering onto explicit asset/context-pack seams.

Changes:

• Added src/server/prompt-loader.ts to load and render named markdown prompt assets (with explicit variable interpolation and caching).
• Migrated interviewer phase system prompts (getSystemPrompt), the observer system prompt, and the side-chat role prompt to use the prompt registry.
• Added a typed context-pack module (src/server/context-pack.ts) and implemented the initial observer-capture context pack builder + renderer.
• Refactored buildObserverContext to render via the new observer-capture context pack to preserve existing output semantics.
• Added tests for prompt loading/interpolation, observer context-pack behavior, and a build-boundary check that prompt assets are copied into the built server runtime.
• Updated the server-runtime Vite build to copy prompt markdown assets into dist/server/prompts.

Technical Notes: Prompt asset resolution is based on import.meta.url at runtime, and the server-runtime build includes a copy step to ensure markdown prompts ship alongside the built server entrypoint.

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[augmentcode]

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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Latest approval commit 204af9d is not an ancestor of 5e5ca78, indicating rewritten history after approval

[graphite-app]

Merge activity

• May 8, 10:38 AM UTC: Graphite rebased this pull request, because this pull request is set to merge when ready.