Consolidate duplicate patterns and simplify codebase (#1317)

* refactor(shared): unify binary downloader and session path storage

- Create binary-downloader.ts for common download/extract logic
- Create session-injected-paths.ts for unified path tracking
- Refactor comment-checker, ast-grep, grep downloaders to use shared util
- Consolidate directory injector types into shared module

* feat(shared): implement unified model resolution pipeline

- Create ModelResolutionPipeline for centralized model selection
- Refactor model-resolver to use pipeline
- Update delegate-task and config-handler to use unified logic
- Ensure consistent model resolution across all agent types

* refactor(agents): simplify agent utils and metadata management

- Extract helper functions for config merging and env context
- Register prompt metadata for all agents
- Simplify agent variant detection logic

* cleanup: inline utilities and remove unused exports

- Remove case-insensitive.ts (inline with native JS)
- Simplify opencode-version helpers
- Remove unused getModelLimit, createCompactionContextInjector exports
- Inline transcript entry creation in claude-code-hooks
- Update tests accordingly

---------

Co-authored-by: justsisyphus <justsisyphus@users.noreply.github.com>

src/agents/sisyphus.ts

@@ -1,8 +1,14 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
-import type { AgentMode } from "./types"
+import type { AgentMode, AgentPromptMetadata } from "./types"
 import { isGptModel } from "./types"
 
 const MODE: AgentMode = "primary"
+export const SISYPHUS_PROMPT_METADATA: AgentPromptMetadata = {
+  category: "utility",
+  cost: "EXPENSIVE",
+  promptAlias: "Sisyphus",
+  triggers: [],
+}
 import type { AvailableAgent, AvailableTool, AvailableSkill, AvailableCategory } from "./dynamic-agent-prompt-builder"
 import {
   buildKeyTriggersSection,