Docs: Generalise ut-core framing — unit-testing core, not HAL-specific

[Ulrond]

Closes #251

What

Reframes the two front-door docs (AGENTS.md, README.md) so ut-core's stated purpose is generic (a C/C++ unit-testing core), with HAL demoted from "the purpose" to the named primary example use case. HAL is only ut-core's main current consumer, not its intent.

Changes (prose only — 11 edits)

AGENTS.md

• Purpose line: "unit-testing framework for RDK HAL components" → "unit-testing core framework for RDK C/C++ components. Its primary current use is testing HAL implementations."
• "new HAL test projects" → "new test projects (e.g. HAL test suites)"
• Architecture diagram label "HAL Test Binary" → "Test Binary"
• "downstream HAL test project" → "downstream test project"; "top-level HAL API repository" → "top-level API repository"
• Directory-tree comments: "HAL test projects" / "HAL API repos" → "test projects" / "API repos"

README.md

• Title "Unit Testing - Hal Testing Suite" → "ut-core - Unit Testing Core Framework"
• Section "## HAL Scope" → "## Primary Use Case — HAL Testing"
• Softened HAL-as-purpose prose (L22, L45, L300, L466) to "component under test (e.g. the HAL)" style wording

Deliberately NOT changed

Load-bearing identifiers and genuine HAL-domain content are untouched: default binary hal_test, Makefile vars HAL_LIB_DIR / -lhal_xxx, downstream repos haltest-wifi / haltest-xxx, naming conventions hal-<component> / haltest-<component>, and docs/pages/hal_unit_testing_requirements.md (a real HAL requirements doc, linked by name elsewhere).

git diff is prose-only — no code, identifiers, or intra-repo links changed.

[Copilot]

Pull request overview

This PR updates the “front-door” documentation to describe ut-core as a general-purpose C/C++ unit-testing core framework, while keeping HAL testing as the primary example use case (per #251).

Changes:

• Reframed README heading and scope section to position HAL testing as the primary use case rather than the framework’s purpose.
• Updated AGENTS.md purpose statement and several downstream/template references to be “test project” / “API repository” instead of HAL-specific wording.
• Minor wording adjustments throughout both docs to use “component under test (e.g. HAL)” phrasing.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
README.md	Updates title/scope framing and adjusts several HAL-specific sentences to “primary use case / component under test” language.
AGENTS.md	Generalizes the stated purpose and various references (architecture label, template/downstream wording) while preserving HAL as the main example consumer.

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[Ulrond]

@bhanucbp @kanjoe24 — adding you as named reviewers; this has been on the team request alone since 16 July. Docs-only change: it reframes ut-core as a general-purpose C/C++ unit-testing core with HAL testing as the primary example, per #251. Review ask: confirm the wording change is one you are happy to stand behind, since it is the front-door description of the project.