Fix clippy warnings blocking release build

[Copilot]

Eliminates all clippy warnings preventing clean release builds. The workspace now compiles with -D warnings.

Changes by category

Unused code removal

• Removed 16 unused imports across transport, SIP, and ACME modules (auto-fixed)
• Prefixed 5 unused variables with _ in handlers and B2BUA

Dead code handling

• Added #[allow(dead_code)] to 4 fields/methods intended for future use (http_port, get_key_authorization, config, server_config)

Trait implementations

• Implemented Display for SdpSession, removed shadowing to_string() method
• Implemented FromStr for Method, removed confusing from_str() method

Code style

• Removed redundant trim() before split_whitespace() in console parser
• Added #[allow(clippy::too_many_arguments)] to 2 functions where parameter groups are contextually coherent

Example: SdpSession trait implementation

Before:

impl SdpSession {
    pub fn to_string(&self) -> String { /* ... */ }
}
// Clippy: inherent_to_string shadows Display trait

After:

impl std::fmt::Display for SdpSession {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { /* ... */ }
}
// Usage: session.to_string() still works via Display trait

Original prompt

Fix the Lint issues that are preventing the release from building.

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