Does God already know every action and decision every human will choose to make in the future? How does this correlate with the objective truth that He has included free-will in the design of His creation? Please provide scriptural support.
Yes, the Bible helps us to understand that God knows every action and decision each of us will make in the future. More than this, God knows even our thoughts ahead of time.
Personal Bible-based Example
And it shall come to pass, that before they call, I will answer; and
while they are yet speaking, I will hear. (Isaiah 65:24, KJV)
This promise in Isaiah was once literally fulfilled in my own experience in a miraculous way. I prayed for guidance on a particular day, and asked God for a particular set of materials I would need if He wanted me to go forward with my desired project. I needed His approval because I was not sure if my desire was merely prompted by my own self-interests or pride that I could do such a great work, and because, if God actually was putting this idea into my heart, the project would require His wisdom. Due to my schedule, I prayed specifically that the materials would come within three weeks from that date; and I promised to tell no one of my request--it was up to God to answer. A week later, a person I had never met, but whom I had emailed a few times, emailed me with the requested materials--and even exceeded what I had asked. When I wrote back to him saying his email had been an answer to prayer, he then wrote again, telling me that several weeks earlier he had felt strongly impressed that he needed to drop everything else and prepare those materials for me, because I needed them.
And here's the interesting part. Several weeks earlier, when God told him I needed those materials, I had not even been thinking of praying for them.
Did God know I would pray that prayer? Evidently, He did. He knew my thoughts before I did.
King Solomon
The Bible says God understands our hearts, thoughts and imaginations.
And thou, Solomon my son, know thou the God of thy father, and serve
him with a perfect heart and with a willing mind: for the LORD
searcheth all hearts, and understandeth all the imaginations of the
thoughts: if thou seek him, he will be found of thee; but if thou
forsake him, he will cast thee off for ever. (1 Chronicles 28:9, KJV)
The LORD knoweth the thoughts of man, that they are vanity. (Psalm
94:11, KJV)
Mary
A prophecy given to Mary, mother of Jesus, showed an indication of her future heart anguish.
(Yea, a sword shall pierce through thy own soul also,) that the
thoughts of many hearts may be revealed. (Luke 2:35, KJV)
King Cyrus
But one of the greatest evidences, in my opinion, is found in the Old Testament story of Cyrus.
The prophet Isaiah lived during the time of King Hezekiah--the same who was granted 15 extra years of life. Following Hezekiah, his wicked son Manasseh reigned for 55 years--the longest reigning monarch in Judah's history, and that of Israel, too. Several kings came afterward, until the time of Nebuchadnezzar of Babylon who took them into captivity, ending the independence of Judah (and Israel's independence had already been lost well before this).
Cyrus was not born until sometime during the seventy-year period of Babylonian captivity. Isaiah's prophecy, therefore, preceded Cyrus' birth by more than a full generation.
That saith of Cyrus, He is my shepherd, and shall perform all my
pleasure: even saying to Jerusalem, Thou shalt be built; and to the
temple, Thy foundation shall be laid. (Isaiah 44:28, KJV)
In this prophecy, God even gives us Cyrus' name. But even his parents were not yet born! The only way for God to have known Cyrus' name so far in advance, was for God to have known the very thoughts of his parents and/or guardians. (Cyrus' story is actually fascinating, as his parents sent him away as a boy to be killed, and he was adopted by a poor peasant when the soldiers could not bring themselves to such a barbarity as to kill the innocent babe. The legend lives online via multiple sources.)
But, as if that were not enough, God predicted more about Cyrus, and used the story to prove God's own foreknowledge!
Thus saith the LORD to his anointed, to Cyrus, whose right hand I
have holden, to subdue nations before him; and I will loose the loins
of kings, to open before him the two leaved gates; and the gates shall
not be shut; (Isaiah 45:1, KJV)
I will go before thee, and make the crooked places straight: I will
break in pieces the gates of brass, and cut in sunder the bars of
iron: (Isaiah 45:2, KJV)
And I will give thee the treasures of darkness, and hidden riches of
secret places, that thou mayest know that I, the LORD, which call thee
by thy name, am the God of Israel. (Isaiah 45:3, KJV)
For Jacob my servant's sake, and Israel mine elect, I have even called
thee by thy name: I have surnamed thee, though thou hast not known me.
(Isaiah 45:4, KJV)
I am the LORD, and there is none else, there is no God beside me: I
girded thee, though thou hast not known me: (Isaiah 45:5, KJV)
That they may know from the rising of the sun, and from the west, that
there is none beside me. I am the LORD, and there is none else.
(Isaiah 45:6, KJV)
What was that about the "gates shall not be shut"? The river that passed under the wall and through the city of Babylon had been cleverly designed with gates to prevent even an under-water entrance on the part of enemies. The city was well built to sustain virtually any siege, with a continual water supply and with its famous hanging gardens and internal agriculture within the city walls. But Cyrus had the bright idea of diverting the river from its course, and, managing to do so temporarily, marched his soldiers under the wall through the riverbed, undetected in the dead of night while the Babylonians were in drunken revelry, thinking themselves secure. And just as God had foretold, those river gates had not been shut.
How could God have known that Cyrus would have such a bright idea? This would only be possible if God knew Cyrus' future thoughts.
Peter
God also knew, better than Peter, that Peter would deny his master thrice.
Jesus said unto him, Verily I say unto thee, That this night, before
the cock crow, thou shalt deny me thrice. (Matthew 26:34, KJV)
Peter didn't even believe it.
Peter said unto him, Though I should die with thee, yet will I not
deny thee. Likewise also said all the disciples. (Matthew 26:35, KJV)
As the Bible says...
The heart is deceitful above all things, and desperately wicked: who
can know it? (Jeremiah 17:9, KJV)
Final Thoughts
Though we do not know our own hearts, God does--even clear into the future. Both the Word of God and personal experience has proven to me that God knows us just as He says He does. And yet, though He knows what we will do, He does not cause us to do it. He has given us a sacred right--the freedom of choice, which is why He asks us to choose Him.