fix: use consistent status labels in update reports

[Brian Krabach (bkrabach)]

Summary

• Use one plain-language Status column across the main Amplifier update report, Modules (local and cached), and Bundles sections.
• Reuse the existing SourceReportState vocabulary, preserving update classification, action eligibility, execution, source inventory, and bundle behavior.
• Remove the obsolete symbol legend from concise and verbose reports; leave utils/display.py and the standalone amplifier module update command unchanged.

Verification

• Focused suite: 83 passed using the existing CLI virtualenv with offline, credential-scrubbed environment settings.
• Prior full suite evidence on the same base: 2075 passed, 3 skipped, 13 deselected, 1 xfailed.
• Reviewed mocked-boundary terminal captures at 80- and 120-column widths for concise and verbose output; no live update, network, LLM, or DTU claims.
• Independent reviewer: PASS.

Scope

• Exactly three files: AGENTS.md, amplifier_app_cli/commands/update.py, and tests/test_update_reporting.py.
• Diff: 243 insertions, 56 deletions.
• Tests cover word labels, shared status vocabulary, concise/verbose output, no legend, and unchanged execution behavior.

Breaking changes

None expected.