get_config_keys() keys its dict by a can:// id on Python and TypeScript, which is unusable across backends and breaks the no-URI rule #346

Describe the bug

get_config_keys() returns a dict keyed by PyConfigKey.id, a can:// URI, on the Python backends (cldk/analysis/python/codeanalyzer/codeanalyzer.py:1672 and the Neo4j twin) and on TypeScript. The generic contract documents that as the key: cldk/analysis/commons/backend.py:163 says "keyed by its id".

Two consequences:

• The key is not stable across backends. The id embeds the application name, which the SDK stamps from the project directory's name when it runs the analyzer, while a graph carries whatever --app-name the operator passed at emit time. So the in-process and Neo4j backends can return the same 336 config keys under entirely disjoint key sets. Java hit exactly this: 336 keys each, zero shared, and the parity test only passed because the reference graph happened to be emitted with a matching name.
• It puts a can:// URI in a public return value, which the 2.0 surface rules exclude everywhere except ref, node_id and next_cursor.

Java now keys by the artifact-relative key instead (pom.xml@key/project.artifactId), with the id still on the model. Python and TypeScript still key by id, so the three languages disagree.

To Reproduce

Not stated in the original issue.

Expected behavior

• The parity test passes with a deliberately mismatched application name
• CHANGELOG records the key change per language with its migration

Additional context

Scope boundary

In scope: the key of the dict get_config_keys() returns on Python and TypeScript, the generic ABC's docstring, and get_config_readers/get_config_uses where they look up by that key. Out of scope: PyConfigKey.id itself, which stays as the model's identity.

Caveats and known risks

• This is a breaking change to a return value's keys on two languages. It belongs in the 2.0 line with a CHANGELOG entry and a one-line migration, not in a patch release.
• Check whether any accessor round-trips the key back into an id before changing it.

Goals

• All three languages key config dicts the same way, and the ABC documents that key
• No can:// URI appears in a public return value outside the sanctioned fields
• A cross-backend test that would have caught the Java case: same project, backends attached from a graph emitted under a different application name, key sets equal