feat: Strongly-typed route path parameters using template literals

[insanerx]

PR Description: Strongly-Typed Path Parameters via TS Template Literal Type Inference

This PR introduces compile-time path parameter type extraction to Volten's routing methods. Developers will now enjoy auto-completion and type safety when accessing ctx.params variables directly based on the route string pattern.

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High-Level Overview

Previously, ctx.params was typed as Record<string, string>, meaning accessing a route parameter did not guarantee the parameter existed on the path, requiring unsafe casts or unchecked property lookups.

This PR adds advanced type level helpers to Volten. When defining a route, such as app.get("/users/:userId/posts/:postId", (ctx) => { ... }), the keys "userId" and "postId" are parsed directly from the path string literal type. ctx.params is then dynamically typed as { userId: string; postId: string }.

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Key Technical Changes

1. Compile-Time Path Parsing Type Helpers (src/core/types.ts)

• Added ExtractParamKeys<T> type helper mapping path segments recursively:
  • Extracts named params (e.g. :id -> "id").
  • Extracts wildcards (e.g. * -> "*").
• Added ExtractParams<T> type helper converting path literals to key-value objects.
• Updated VoltenHandler, PreflightHandler, and ErrorHandler signatures to propagate the generic path string literal parameter P.

2. Router API Generic Integrations (src/core/router.ts)

• Updated all HTTP verb router methods (get, post, patch, put, delete) to define <P extends string> generics.
• Handlers passed to routes now bind to VoltenHandler<P>[].

3. Context Params Mapping (src/utils/requestCtx.ts)

• Updated RequestContext to accept generic parameter <P extends string = string>.
• Changed ctx.params property typing to match ExtractParams<P> instead of general Params.

4. Tests Added (tests/unit/core/types.test.ts [NEW])

• Added compile-time types evaluation checks verifying single parameters, nested parameters, and wildcards.
• Added compiler checks for router handlers.

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Breaking Changes

• Type Parameter Requirements: Custom wrappers around VoltenHandler might require updating signatures to accept or default a type parameter P extends string.
• Type Casts: Code attempting to assign ctx.params to a generic dictionary might require casting or widening if the route path is statically typed.