Update docs with the contextual token resolver config

[rads-1996]

No description provided.

[Copilot]

Pull request overview

This PR updates the documentation for Agent 365 (A365) configuration to include the new contextual token resolver option, clarifying its behavior and precedence relative to the existing token resolver.

Changes:

• Document a365_contextual_token_resolver in the main README configuration table, including precedence rules.
• Update the A365 migration guide example and checklist to reference the contextual resolver.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
README.md	Adds a365_contextual_token_resolver to the configuration reference and clarifies precedence vs a365_token_resolver.
MIGRATION_A365.md	Updates migration example and checklist to include/mention the contextual resolver option.

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[github-actions]

Performance comparison

Threshold: regressions >15.0% on gating scenarios fail the build. Higher ops/s is better; positive Δ means the PR is slower.

Scenario	Gating	Baseline (ops/s)	Candidate (ops/s)	Δ %	Status
azure_monitor_log	yes	35,634.1	35,345.7	+0.82%	✅
azure_monitor_span	yes	162,364.0	163,158.8	-0.49%	✅
otel_log	no	42,890.8	42,744.2	+0.34%	✅
otel_span	no	43,890.4	44,338.0	-1.01%	✅

[nikhilNava]

Approved with comments