remove LocalPath and rename Origin to HostHeaderValue

[Erwinvandervalk]

What issue does this PR address?

There's confusion around certain terms:

• LocalPath is confusing because it can either mean a path relative to the BFF but can also be interpreted as a path locally to the filesystem.
• Origin is confusing because people think it maps to the origin header but actually it maps to the origin data structure. Renamed it to HeaderValue, even though we also have the scheme inside it.
• MappedToOrigin is confusing, because it implies that it maps to an origin header, but actually it maps to the Domain header.
• Made the language MappedTo into more imperative language: MapTo
• Some people add duplicate mappings. This should result in a warning in the logs.

fixes: https://github.com/DuendeSoftware/products-private/issues/2272
fixes: https://github.com/DuendeSoftware/products-private/issues/2357

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[Copilot]

Pull Request Overview

This PR renames several confusing terminology throughout the BFF codebase to improve clarity and reduce confusion around domain-specific concepts:

• LocalPath → PathMatch: Clarifies that this represents a path pattern for matching rather than a filesystem path
• Origin → HostHeaderValue: Distinguishes from HTTP origin headers and CORS concepts while better describing the actual data structure (scheme + host + port)
• MappedToOrigin/MappedToPath → MapTo/MapToHost/MapToPath: Changes from passive "mapped to" language to imperative "map to" verbs
• SelectionCriteria → MatchingCriteria: More clearly describes the purpose of determining frontend selection
• FrontendSelectionCriteria → FrontendMatchingCriteria: Aligns with the above naming convention

Reviewed Changes

Copilot reviewed 54 out of 55 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
Test infrastructure files	Update test data builders and configuration to use new terminology
Public API verification files	Update expected public API surface to reflect terminology changes
Template files	Update configuration examples to use PathString instead of LocalPath
Core BFF source files	Rename types, properties, and methods throughout the codebase
Documentation	Update upgrade guide to reflect API changes
Performance/benchmark files	Update test hosts and fixtures with new terminology

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[Copilot]

Pull Request Overview

Copilot reviewed 56 out of 57 changed files in this pull request and generated 1 comment.

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[Copilot]

Pull Request Overview

Copilot reviewed 60 out of 61 changed files in this pull request and generated 3 comments.

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