hrw: Supports indexed query parameters as conds

[zwoop]

Co-author / ideas: Miles

[Copilot]

Pull request overview

This PR adds support for extracting individual query parameter values in the header_rewrite plugin using indexed query parameter syntax. The feature allows conditions to match against specific query parameter values using the syntax %{CLIENT-URL:QUERY:<param_name>} instead of matching against the entire query string.

Changes:

• Introduced query parameter caching mechanism to efficiently parse and retrieve individual query parameter values
• Extended URL qualifier syntax to support sub-keys for QUERY components (e.g., QUERY:version)
• Added cache invalidation when URL query strings are modified via operators

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
plugins/header_rewrite/resources.h	Added query parameter caching infrastructure and get_query_param() method to Resources class
plugins/header_rewrite/resources.cc	Implemented query parameter parsing and caching logic using swoc::TextView
plugins/header_rewrite/conditions.h	Added _query_param member to store the specific parameter name for QUERY sub-key
plugins/header_rewrite/conditions.cc	Extended URL qualifier parsing to support sub-key syntax and modified query evaluation to use cached parameter values
plugins/header_rewrite/operators.cc	Added cache invalidation calls when query strings are modified by set-destination and rm-destination operators
doc/admin-guide/plugins/header_rewrite.en.rst	Documented the new QUERY sub-key syntax with usage examples

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[zwoop]

I addressed Co-Pilot's suggestions, most where very nit-picky, one was wrong. :)

[zwoop]

[approve ci osx]