docs: align the README lead and repository description with the v2 CLI/application framework #569

Goal

Make the first thing a newcomer reads describe what v2 actually offers: a declarative CLI, typed configuration, and lifecycle framework, not only a helper-function bag.

Background

The README lead (lines 13-18) says "Reusable Bash standard library for reliable shell scripts… logging, error handling, safe command execution, filesystem edits, Git helpers, string utilities, temp paths, cleanup hooks, and import conventions". The "Libraries" list (from line 26) puts cli and app ninth and tenth. The GitHub description is "Sourceable Bash helper libraries for reliable shell scripts: error handling, logging, files, Git, strings, temp paths, cleanup hooks, and command runners" and has no topic for configuration or lifecycle. Meanwhile the v2 quickstart, the generated scaffold, and base-bash-libs-demo all revolve around base_cli_*/base_app_* with the base-bash launcher. A visitor who reads the README and then opens the demo sees a different product. The README also leads with install detail before a minimal runnable example of the headline feature.

Scope

• Rewrite the README opening: one sentence of value proposition covering CLI contract, typed config, lifecycle/cleanup, and safe primitives, followed by a ten-line base-bash example (the demo's minimal consumer) and its output.
• Reorder the Libraries list as layers (foundation: std; building blocks; application framework: cli, app) with a one-line "start with" recommendation.
• Align the GitHub repository description and topics with the new lead.
• Keep base_manifest.yaml/docs-contract assertions in sync.

Acceptance Criteria

• The README opening and repository description describe the same product as the quickstart and the demo.
• The example in the README is executed by the docs contract or a smoke test.
• base-bash-libs-demo wording (README line 28-37, "Why base-bash-libs?") is cross-checked against the new lead.

Validation

• ./tests/docs-contract.sh
• ./tests/validate.sh
• Demo repo: ./tests/docs-contracts.sh

Non-Goals

• Do not rename the project or change the API.
• Do not remove the stdlib-only usage path.

Project Fields

• Status: Ready
• Priority: P2
• Area: Docs
• Initiative: Adoption Polish
• Size: M

Agent Assignment

• Assignee: @codeforester