feat: connection over rest

[mayankansys]

Context

PyFluent currently supports a gRPC transport. This PR adds a parallel REST(HTTP/HTTPS) transport layer to exercise the same settings API over HTTP/HTTPS against the SimBA web server, keeping the settings tree transport-agnostic.

This PR covers Step 1 and Step 2 of Issue #4959:

• Step 1 — Introduce a working REST client that can read/write settings and invoke command/query endpoints.
• Step 2 — Provide a launcher/session so the existing settings tree can run over REST without changing the settings tree implementation.

Change Summary

• Added a REST client that builds requests, hashes auth tokens into the Authorization header, parses errors, and supports retry on transient failures for safe methods.
• Added a lightweight REST launcher + connection path.
• Added integration tests (real-server) and mocked/unit tests to validate request construction and error handling in CI.

Rationale

Keep REST support isolated, simple, and low risk:

• no changes to the settings tree core logic,
• REST and gRPC can coexist,
• CI can catch regressions without requiring a live server.

Impact

What changes for users

• New public APIs to launch/connect via REST (HTTP/HTTPS).
• Settings reads/writes and command execution can be performed over HTTP/HTTPS.

What does NOT change

• The settings tree core remains unchanged.
• Existing gRPC launch/session APIs remain unchanged.

Limitations (out of scope)

• Some server behaviors (shutdown timing, confirmation prompts) are server-driven and may vary by version/config.

[codacy-production]

Up to standards ✅

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

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[prmukherj]

@mayankansys, no need of these error handling logic. Just fall back to the server implmenentation.

[prmukherj]

@mayankansys, there should be a way to bypass most of this code in this method and just call pyfluent.launch_fluent with required additional arguments.