fix: render solid rule borders in disabled-SSL warning banner

[anxkhn]

## What

When SSL verification is disabled, `create_ssl_context` (in
`python/packages/kagent-adk/src/kagent/adk/models/_ssl.py`) logs a warning banner
that is meant to be framed by three 60-character rules of `=`. Because of an
operator-precedence issue those rules render as a jagged column of single `=`
signs instead of solid lines. This makes a security-relevant warning look
malformed in the logs. This PR fixes the borders and adds a regression test.

## Why it happens

Each rule is written as a string literal immediately followed by `"=" * 60`, for
example:

```python
logger.warning(
    "\n"
    "=" * 60 + "\n"
    ...
)

Python applies implicit string-literal concatenation before the * repetition,
so "\n" "=" * 60 parses as ("\n=") * 60, i.e. sixty \n= pairs, rather than a
newline followed by a 60-character rule. All three rules in the banner (top,
separator, and bottom) are affected, so the logged warning looks like this:

=
=
=
... (60 rows)
⚠️  SSL VERIFICATION DISABLED ⚠️
=
=
... (60 rows)

The fix

Add an explicit + before each "=" * 60 so the repetition applies to "="
alone. All three borders now render as solid 60-character rules:

============================================================
⚠️  SSL VERIFICATION DISABLED ⚠️
============================================================
SSL certificate verification is disabled.
This should ONLY be used in development/testing.
Production deployments MUST use proper certificates.
============================================================

The change is limited to the string framing; no logging behavior, return value,
or TLS logic changes.

Testing

Added test_ssl_context_disabled_warning_banner_borders, which captures the
warning via caplog and asserts the banner contains exactly three solid
60-character = rules and no stray single-= rows. It fails on the current code
and passes with the fix.

cd python
uv run pytest packages/kagent-adk/tests/unittests/models/test_ssl.py -q
# 7 passed

ruff check and ruff format --diff are clean on both changed files.

[Copilot]

Pull request overview

Fixes the disabled-SSL-verification warning banner in create_ssl_context so its framing rules render as solid 60-character = lines (rather than a jagged column caused by implicit string-literal concatenation precedence), and adds a regression test to lock in the correct formatting.

Changes:

• Adjust warning-banner string construction in create_ssl_context to ensure "=" * 60 repeats only "=" (not "\n=").
• Add a regression test that captures the warning via caplog and asserts exactly three 60-character = runs are present (and no stray single-= rows).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
python/packages/kagent-adk/src/kagent/adk/models/_ssl.py	Fixes operator-precedence/implicit-concatenation issue so the warning banner borders render as solid rules.
python/packages/kagent-adk/tests/unittests/models/test_ssl.py	Adds a caplog-based regression test to verify the banner contains exactly three solid 60-character rule borders.

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[peterj]

makes sense, but we probably don't really need a unit test for this