feat(galileo-a2a): rebrand to SPLUNK_AO_* env vars and SplunkAOSpanProcessor (HYBIM-716)

[adityamehra]

Core package:

• Rename GALILEO_OBSERVE_KEY -> SPLUNK_AO_OBSERVE_KEY in _constants.py
• Rename GALILEO_* context vars to SPLUNK_AO_* in _context.py and _client_patches.py
• Update pyproject.toml: galileo dependency -> splunk-ao, update classifiers

Examples:

• examples/.env.example: replace SPLUNK_AO_CONSOLE_URL with SPLUNK_AO_API_URL (direct API host is required for self-hosted deployments)

Documentation (README.md):

• Replace GalileoSpanProcessor -> SplunkAOSpanProcessor in all code examples
• Replace GALILEO_* env vars -> SPLUNK_AO_* in configuration table
• Add SPLUNK_AO_API_URL row (required for self-hosted)
• Update all Galileo brand mentions to Splunk AO

Tests:

• Update all GALILEO_* env var references to SPLUNK_AO_* in conftest.py and test_context.py

[adityamehra]

@fercor-cisco Do I need to update the package name to splunk-ao-a2a?

[adityamehra]

Done — PyPI package renamed to splunk-ao-a2a in pyproject.toml. The Python import module name stays galileo_a2a for now to avoid breaking downstream consumers until a full module rename is planned.

[adityamehra]

We update the INSTRUMENTOR_NAME to splunk-ao-a2a but here we still use galileo-a2a. How will it affect the release and package name?

[adityamehra]

Fixed — pyproject.toml now has name = "splunk-ao-a2a". INSTRUMENTOR_NAME was already updated to "splunk-ao-a2a" in the previous commit. Both are now consistent.

[adityamehra]

We need to review toml for galileo-a2a and make sure we update Galileo references to splunk-ao where possible. Reset the initial version to 0.1.0 and tags to refer to splunk-ao wherever possible

[adityamehra]

Done — full pyproject.toml cleanup applied:

• name → splunk-ao-a2a, version → 0.1.0
• Description, authors (Splunk Inc.), repository URL → splunk/splunk-ao-python
• galileo dependency → splunk-ao>=2.0.0,<3.0.0 (incl. dev group)
• tool.uv.sources key → splunk-ao
• Pytest env vars → SPLUNK_AO_*
• tag_format / commit_message → splunk-ao-a2a-v{version}
• README badges and pip install → splunk-ao-a2a