Android Documentation Improvements and other fixes

[psiddh]

1. Make Android doc more Dev focused / friendly
   (Quick Start Navigation , More Clear Pathfinding & Logical Flow for Devs)
2. Update links to be relevant in Android sections
3. Fix the broken vulkan & coreML links from Android & iOS flow
4. Fix navigation related issues

Summary

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Test plan

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[pytorch-bot]

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❗ 1 Active SEVs

There are 1 currently active SEVs. If your PR is affected, please view them below:

• [ROCm][CI] Machines under the label linux.rocm.gpu.2 are undergoing maintenance.

❌ 6 New Failures, 6 Unrelated Failures

As of commit 5791a6e with merge base 98baab7 ():

NEW FAILURES - The following jobs have failed:

• pull / test-samsung-models-linux / linux-job (gh)
  RuntimeError: Command docker exec -t 53cc94f9c22405fa149a2ccd1618b479d4158522c8e8183ecfd904965e4d4c75 /exec failed with exit code 1
• pull / unittest-arm-backend-with-no-fvp (test_pytest_models) / linux-job (gh)
  RuntimeError: Command docker exec -t 5359502768d0dccf5c8307578d1e1f99a2fb124ec78bce607c35c9f32beb4fed /exec failed with exit code 1
• pull / unittest-nxp-neutron / linux-job (gh)
  RuntimeError: Command docker exec -t 05c7331b3c743a9973c5a70ead0be51bf4d101ad900a5236e839036b5c59c0d0 /exec failed with exit code 1
• Test CUDA Builds / export-voxtral-cuda-non-quantized / linux-job (gh)
  RuntimeError: Command docker exec -t a69d1789592582405576e7040136e7a55e3080636fbab3e6de099576758c9f7b /exec failed with exit code 2
• Test CUDA Builds / export-voxtral-cuda-quantized-int4-tile-packed / linux-job (gh)
  RuntimeError: Command docker exec -t 288435cdeb3b097eaa074f75990550ea51842564297b1caa1aa29b76db0c816b /exec failed with exit code 2
• Test CUDA Builds / export-voxtral-cuda-quantized-int4-weight-only / linux-job (gh)
  RuntimeError: Command docker exec -t a86bd28d76366e651a3ba5274abb21d9f7e5c615ce08eadcd9590f2a18d2c720 /exec failed with exit code 2

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / android / run-emulator (gh) (trunk failure)
  The process '/usr/bin/sh' failed with exit code 255
• pull / test-binary-size-linux-gcc / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / test-openvino-linux / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / test-setup-linux-gcc / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / unittest / linux / linux-job (gh) (trunk failure)
• pull / unittest-editable / linux / linux-job (gh) (trunk failure)

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