Data flow: Add FeatureEscapesSourceCallContext(OrEqualSourceSinkCallContext) flow feature

[hvitved]

This PR adds two new flow features FeatureEscapesSourceCallContext and FeatureEscapesSourceCallContextOrEqualSourceSinkCallContext.

The former implies that the sink must be reached from the source by escaping the source call context, that is, flow must either return from the callable containing the source or use a jump-step before reaching the sink. The latter is the disjunction of the former and the existing FeatureEqualSourceSinkCallContext flow feature.

This allows us to greatly simplify the Rust query AccessAfterLifetime.ql, in addition to improving performance and precision of said query, since filtering of results now happen as part of the data flow computation instead of an ad-hoc after-the-fact filter.

DCA for all languages except Rust is uneventful, and for Rust it shows that we achieve a significant speedup.

[Copilot]

Pull request overview

This PR extends the shared global data flow implementation with two new flow features to constrain results based on whether flow escapes the source call context, and updates the Rust AccessAfterLifetime query to use these features for simpler and faster filtering.

Changes:

• Add FeatureEscapesSourceCallContext and FeatureEscapesSourceCallContextOrEqualSourceSinkCallContext as new flow configuration features in shared dataflow internals.
• Update shared dataflow internals to track and enforce the new “escapes source call context” constraint during flow computation.
• Simplify Rust AccessAfterLifetime.ql by relying on the new flow feature and adjust Rust tests/expected output accordingly.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
shared/dataflow/codeql/dataflow/internal/DataFlowImplStage1.qll	Adds Stage 1 predicate plumbing for the new escape-context feature.
shared/dataflow/codeql/dataflow/internal/DataFlowImplCommon.qll	Defines the new flow feature types and public feature classes.
shared/dataflow/codeql/dataflow/internal/DataFlowImpl.qll	Implements summary-context handling to enforce the new feature during dataflow.
shared/dataflow/change-notes/2026-03-04-flow-feature-escapes-source-call-context.md	Adds changelog entry documenting the new flow features.
rust/ql/src/queries/security/CWE-825/AccessAfterLifetime.ql	Switches the query to use the new flow feature and removes ad-hoc filtering logic.
rust/ql/test/query-tests/security/CWE-825/lifetime.rs	Updates inline expectations to reflect the new/changed result.
rust/ql/test/query-tests/security/CWE-825/AccessAfterLifetime.expected	Updates expected output to match new analysis results.

[aschackmull]

A few nits, otherwise LGTM.