Escape string path parameters by segment type

[renaudhartert-db]

Summary

Percent-encodes generated string path parameters according to their OpenAPI segment semantics. Ordinary values occupy one URL segment, while explicit and patterned multi-segment resource names preserve / separators and escape each segment independently.

Why

Generated clients previously interpolated most string path parameters directly into request paths. Reserved characters such as /, #, ?, and spaces could therefore change the URL structure or route requests to the wrong endpoint.

Treating every string as a single segment is also incorrect: hierarchical resource names such as projects/p1 and projects/p1/branches/b1 rely on / separators to match their routes. This PR uses the generator's segment metadata, including resource patterns fixed by universe#2437239, to distinguish those cases.

What changed

Interface changes

• Adds httpclient.EncodeSingleSegmentPathParameter(string) string for values that must remain within one URL path segment.
• Documents the existing httpclient.EncodeMultiSegmentPathParameter behavior.

Behavioral changes

• Generated string and configured account ID path parameters are percent-encoded as single segments by default; embedded / characters become %2F.
• Explicit multi-segment parameters and patterned resource bindings such as {parent=projects/*} preserve / as hierarchy separators while escaping each segment.
• Numeric and boolean path parameters are unchanged.

Internal changes

• Regenerates affected API implementations and generated test services.
• Removes governed-tag escaping overrides now covered by generated single-segment serialization; retaining them would double-encode the path value.
• Updates long-running-operation fixtures to expect escaped operation names.

How is this tested?

• make fmt
• make test (1,493 tests passed)
• make lint
• bazel test //openapi/genkit/apimodel:apimodel_test //openapi/genkit/rendering/gobeta:gobeta_test --tool_tag=ai-agent --test_output=errors --noshow_progress --noshow_loading_progress
• Audited the pinned OpenAPI resource patterns against generated SDK paths to verify hierarchical bindings use multi-segment encoding and constant/* bindings remain single-segment.

[github-actions]

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Trigger:
go/deco-tests-run/sdk-go

Inputs:

• PR number: 1811
• Commit SHA: 7908fd21fea49c808201689d9767753a25baf3d5

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[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 15 days if no further activity occurs. If this PR is still relevant, please leave a comment or push new changes to keep it open. Thank you for your contributions.

[github-actions]

This pull request has been automatically closed because it remained stale for 15 days with no further activity. Feel free to reopen it if you'd like to continue working on it.